Using mixtures of e/z isomers to obtain quantitatively specific products by combined asymmetric hydrogenations

ABSTRACT

The present invention relates to a process of manufacturing compound having stereogenic centres from a mixture of E/Z isomers of unsaturated compounds having prochiral double bonds. The hydrogenation product has a specific desired configuration at the stereogenic centres. The process involves two asymmetric hydrogenation steps. The process is very advantageous in that it forms the desired chiral product from a mixture of stereoisomers of the starting product in an efficient way.

TECHNICAL FIELD

The present invention relates to field of asymmetrical hydrogenation and the synthesis of chiral ketones, aldehydes, acetals and ketals.

BACKGROUND OF THE INVENTION

Chiral ketones and aldehydes are very important products or intermediates for the synthesis of compounds in the fields of flavours and fragrances or pharmaceutical products and vitamins.

These products have stereogenic centres which makes their properties very unique.

One possibility of creating stereogenic carbon centres is addition of compounds, particularly of molecular hydrogen, to prochiral carbon-carbon double bonds of suitable starting materials.

Classic chemical reactions result mainly in mixtures of the configuration at said stereogenic centres and require the use of expensive separation processes.

Therefore for a long time there has been a large demand for highly stereoselective reactions leading to specific stereogenic configurations.

WO 2006/066863 A1 discloses an asymmetric hydrogenation of alkenes to yield specific configurations of the stereogenic centres being formed by the hydrogenation.

However, technically alkenes very often are mixtures of E and Z isomers.

SUMMARY OF THE INVENTION

Therefore, the problem to be solved by the present invention is to offer a process which allows using mixtures of E/Z isomers of unsaturated compounds having prochiral carbon-carbon double bonds to yield a hydrogenated product having the desired configuration at the stereogenic centre being formed by the hydrogenation.

Surprisingly it has been shown that this problem can be solved by the process according to claim 1.

In this process mixtures of isomers can be used and all isomers can be converted to the desired product.

It has been shown that particularly the hydrogenation of acetals and ketals are very effective and offer a much better efficiency of the chiral complexes used in the asymmetric hydrogenations.

Further aspects of the invention are subject of further independent claims. Particularly preferred embodiments are subject of dependent claims.

DETAILED DESCRIPTION OF THE INVENTION

In a first aspect the present invention relates to a process of manufacturing a compound of formula (I-A) or (I-B) or an acetal or a ketal thereof from a mixture of E/Z isomers of compound of formula (I) or (II) or an acetal or a ketal thereof

-   -   wherein Q stands for H or CH₃ and m and p stand independently         from each other for a value of 0 to 3 with the proviso that the         sum of m and p is 0 to 3, and where a wavy line represents a         carbon-carbon bond which is linked to the adjacent carbon-carbon         double bond so as to have said carbon-carbon double bond either         in the Z or in the E-configuration and where the substructures         in formula (I) and (II) represented by s1 and s2 can be in any         sequence;     -   and wherein the double bond having dotted lines (         ) in formula (I) or (II) represent either a single carbon-carbon         bond or a double carbon-carbon bond;         comprising the steps

-   a) separating the isomers having E-configuration from the isomers     having Z-isomers in the mixture of isomers of compound of     formula (I) or (II) or the acetal or ketal thereof;

-   b) submitting the isomers having the E-configuration of compound of     formula (I) or (II) or the acetal or ketal thereof to hydrogenation     by molecular hydrogen in the presence of a chiral iridium complex of     formula (III) having the S-configuration at the stereogenic centre     indicated by *;

-   c) submitting the isomers having the Z-configuration of compound of     formula (I) or (II) or the acetal or ketal thereof to hydrogenation     by molecular hydrogen in the presence of a chiral iridium complex of     formula (III) having the R-configuration at the stereogenic centre     indicated by *;     and optionally step d)

-   d) combining the hydrogenated products of step b) and c);

-   -   wherein     -   n is 1 or 2 or 3, preferred 1 or 2;     -   X¹ and X² are independently from each other hydrogen atoms,         C₁₋₄-alkyl, C₅₋₇-cycloalkyl, adamantyl, phenyl (optionally         substituted with one to three C₁₋₅-alkyl, C-alkoxy.         C₁₋₄-perfluoroalkyl groups and/or one to five halogen atoms)),         benzyl, 1-naphthyl, 2-naphthyl, 2-furyl or ferrocenyl;     -   Z¹ and Z² are independently from each other hydrogen atoms,         0₁₋₆-alkyl or C₁₋₅-alkoxy groups;     -   or Z¹ and Z² stand together for a bridging group forming a 5 to         6 membered ring;     -   Y^(⊖) is an anion, particularly selected from the group         consisting of halide, PF₆ ⁻, SbF₆ ⁻,         tetra(3,5-bis(trifluoromethyl)phenyl)borate(BAr_(F) ⁻), BF₄ ⁻,         perfluorinated sulfonates, preferably F₃C—SO₃ ⁻ or F₉C₄—SO₃ ⁻;         ClO₄ ⁻, Al(OC₆F₅)₄ ⁻, Al(OC(CF₃)₃)₄ ⁻, N(SO₂CF₃)₂ ⁻N(SO₂C₄F₉)₂ ⁻         and B(C₆F₅)₄ ⁻;     -   R¹ represents either phenyl or o-tolyl or m-tolyl or p-tolyl or         a group of formula (IVa) or (IVb) or (IVc)

-   -   -   wherein R² and R³ represent either both H or a C₁-C₄-alkyl             group or a halogenated C₁-C₄-alkyl group or represent a             divalent group forming together a 6-membered cycloaliphatic             or an aromatic ring which optionally is substituted by             halogen atoms or by C₁-C₄-alkyl groups or by C₁-C₄-alkoxy             groups         -   R⁴ and R⁵ represent either both H or a C₁-C₄-alkyl group or             a halogenated C₁-C₄-alkyl group or a divalent group forming             together a 6-membered cycloaliphatic or an aromatic ring             which optionally is substituted by halogen atoms or by             C₁-C₄-alkyl groups or by C₁-C₄-alkoxy groups;         -   R⁶ and R⁷ and R⁸ represent each a C₁-C₄-alkyl group or a             halogenated C₁-C₄-alkyl group;         -   R⁹ and R¹⁹ represent either both H or a C₁-C₄-alkyl group or             a halogenated C₁-C₄-alkyl group or a divalent group forming             together a 6-membered cycloaliphatic or an aromatic ring             which optionally is substituted by halogen atoms or by             C₁-C₄-alkyl groups or by C₁-C₄-alkoxy groups;

    -   and wherein * represents a stereogenic centre of the complex of         formula (III).

The sum of m and p is preferably 0 to 2, particularly 0 or 1.

The term “independently from each other” in this document means, in the context of substituents, moieties, or groups, that identically designated substituents, moieties, or groups can occur simultaneously with a different meaning in the same molecule.

A “C_(x-y)-alkyl” group is an alkyl group comprising x to y carbon atoms, i.e., for example, a C₁₋₃-alkyl group is an alkyl group comprising 1 to 3 carbon atoms. The alkyl group can be linear or branched. For example —CH(CH₃)—CH₂—CH₃ is considered as a C₄-alkyl group.

A “C_(x-y)-alkylene” group is an alkylene group comprising x to y carbon atoms, i.e., for example C₂-C₆ alkylene group is an alkyl group comprising 2 to 6 carbon atoms. The alkylene group can be linear or branched. For example the group —CH(CH₃)—CH₂— is considered as a C₃-alkylene group.

A “phenolic alcohol” means in this document an alcohol which has a hydroxyl group which is bound directly to an aromatic group.

The term “stereogenic centre” as used in this document is an atom, bearing groups such that interchanging of any two of the groups leads to a stereoisomer. Stereoisomers are isomeric molecules that have the same molecular formula and sequence of bonded atoms (constitution), but that differ in the three-dimensional orientations of their atoms in space.

Cis/trans isomers are configurational isomers having different orientation at the double bond. In this document the term “cis” is equivalently used for “Z” and vice versa as well as “trans” for “E” and vice versa. Therefore, for example the term “cis/trans isomerization catalyst” is equivalent to the term “E/Z isomerization catalyst”.

The terms “E/Z”, “cis/trans” and “R/S” denote mixtures of E and Z, of cis and trans, and of R and S, respectively.

In case identical labels for symbols or groups are present in several formulae, in the present document, the definition of said group or symbol made in the context of one specific formula applies also to other formulae which comprises said same label.

In the present document any single dotted line represents the bond by which a substituent is bound to the rest of a molecule.

The process of manufacturing compound of formula (I-A) or (I-B) or an acetal or a ketal thereof uses a mixture of E/Z isomers of compound of formula (I) or (II) or an acetal or a ketal thereof as staring material.

The compound of formula (I) or (II) or the acetals or ketals thereof have prochiral carbon-carbon double bonds.

Particularly preferred is compounds of (II), particularly being selected from the group consisting of 6,10-dimethylundeca-3,5,9-trien-2-one, 6,10-dimethylundeca-5,9-dien-2-one, 6,10-dimethylundec-5-en-2-one, 6,10-dimethylundec-3-en-2-one, 6,10-dimethylundec-3,5-diene-2-one, 6,10,14-trimethylpentadeca-5,9,13-trien-2-one, 6,10,14-trimethylpentadeca-5,9-dien-2-one, 6,10,14-trimethylpentadec-5-en-2-one and (R)-6,10,14-trimethylpentadec-5-en-2-one as well as all their possible E/Z-isomers.

Most preferably the compound of formula (I) or (II) is selected from the group consisting of 3,7-dimethyloct-6-enal, 3,7-dimethylocta-2,6-dienal, 3,7-dimethyloct-2-enal, 6,10-dimethylundeca-3,5,9-trien-2-one, 6,10-dimethylundeca-5,9-dien-2-one, 6,10-dimethylundec-5-en-2-one, 6,10-dimethylundec-3-en-2-one, 6,10,14-trimethylpentadeca-5,9,13-trien-2-one, 6,10,14-trimethylpentadeca-5,9-dien-2-one, 6,10,14-trimethylpentadec-5-en-2-one and (R)-6,10,14-trimethylpentadec-5-en-2-one as well as all their possible E/Z-isomers.

Most preferably the compound of formula (I) or (II) is a ketone.

Acetal/Ketal Formation

The formation of a ketal from a ketone, or of an acetal from an aldehyde, per se, is known to the person skilled in the art.

The ketal or acetal of compound of formula (I) or (II) can be preferably formed from the above mentioned compound of formula (I) or (II) and an alcohol.

It is known to the person skilled in the art that there are alternative routes of synthesis for acetal or ketals. In principle, the ketal and acetals can also be formed by treating a ketone or an aldehyde with ortho-esters or by trans-ketalization such as disclosed for example in Perio et al., Tetrahedron Lett., 1997, 38 (45), 7867-7870 or in Lorette, J. Org. Chem. 1960, 25, 521-525, the entire content of both is hereby incorporated by reference.

Preferably the ketal or acetal is formed from the above mentioned compound of formula (I) or (II) and an alcohol.

The alcohol used for the ketal or acetal formation can, principally, be any alcohol, i.e. the alcohol may comprise one or more hydroxyl groups. The alcohol may be a phenolic alcohol or an aliphatic or cycloaliphatic alcohol. Preferably, however, the alcohol has one hydroxyl groups (=monol) or two hydroxyl groups (=diol).

In case the alcohol has one hydroxyl group, the alcohol is preferably an alcohol which has 1 to 12 carbon atoms. Particularly, the alcohol having one hydroxyl group is selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, pentane-1-ol, 3-methylbutane-1-ol, 2-methylbutane-1-ol, 2,2-dimethylpropan-1-ol, pentane-3-ol, pentane-2-ol, 3-methylbutane-2-ol, 2-methylbutan-2-ol, hexane-1-ol, hexane-2-ol, hexane-3-ol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 4-methyl-1-pentanol, 3-methyl-2-pentanol, 4-methyl-2-pentanol, 2-methyl-3-pentanol, 2,2-dimethyl-1-butanol, 2,3-dimethyl-1-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, and all structural isomers of heptanal, octanol and halogenated C₁-C₈-alkyl alcohols, particularly 2,2,2-trifluoroethanol. Particularly suitable are primary or secondary alcohols. Preferably primary alcohols are used as alcohols with one hydroxyl group. Particularly methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol or 2,2,2-trifluoroethanol, preferably methanol, ethanol, 1-propanol, 1-butanol or 2,2,2-trifluoroethanol, are used as alcohols with one hydroxyl group.

In another embodiment the alcohol is a diol. Preferably the diol is selected from the group consisting of ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, butane-1,3-diol, butane-1,2-diol, butane-2,3-diol, 2-methylpropane-1,2-diol, 2-methylpropane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 1,2-dimethylpropane-1,3-diol, 3-methylpentane-2,4-diol and 2-(hydroxymethyl)-cyclohexanol, benzene-1,2-diol and cyclohexane-1,2-diols. From two cyclohexane-1,2-diols the preferred stereoisomer is syn-cyclohexane-1,2-diol (=cis-cyclohexane-1,2-diol).

The two hydroxyl group are in one embodiment bound to two adjacent carbon atoms, hence these diols are vicinal diols. Vicinal diols form a 5 membered ring in a ketal or acetal.

Particularly suitable are vicinal diols which are selected from the group consisting of ethane-1,2-diol, propane-1,2-diol, butane-1,2-diol, butane-2,3-diol, 2-methylpropane-1,2-diol, benzene-1,2-diol and syn-cyclohexane-1,2-diol, particularly ethane-1,2-diol.

Other particularly suitable are diols, in which the hydroxyl groups are separated by 3 carbon atoms, and, hence, form a very stable 6 membered ring in a ketal or acetal. Particularly suitable diols of this type are propane-1,3-diol, butane-1,3-diol, 2-methylpropane-1,3-diol, 2-methylbutane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 1,2-dimethylpropane-1,3-diol, 3-methylpentane-2,4-diol and 2-(hydroxymethyl)cyclohexanol.

Preferably primary alcohols are used as diols.

In one embodiment the acetal or ketal of the compound of formula (I) or (II) is obtained by the reaction of the compound of formula (I) or (II) with an alcohol, particularly a monol or a diol, preferably an alcohol selected from the group consisting of is halogenated C₁-C₈-alkyl alcohol or which is selected from the group consisting of ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, butane-1,3-diol, butane-1,2-diol, butane-2,3-diol, 2-methylpropane-1,2-diol, 2-methylpropane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 1,2-dimethylpropane-1,3-diol, 3-methylpentane-2,4-diol and 2-(hydroxymethyl)cyclohexanol, benzene-1,2-diol and cyclohexane-1,2-diols.

The reaction conditions and stoichiometry used for the acetal or ketal formation are known to the person skilled in the art. Particularly the acetal or ketal is formed under the influence of an acid.

The preferred ketal or acetal of formula (I) or (II) are of formula (XI) or (XII)

The groups and symbols in formula (XI) and (XII) have the same meaning as defined before in this document for formula (I) and (II).

Q¹ and Q² stand either individually both for a C₁-C₁₀ alkyl group or a halogenated C₁-C₁₀ alkyl group;

-   -   or form together a C₂-C₆ alkylene group or a C₆-C₈ cycloalkylene         group.

Q¹ and Q² stand particularly for

either a linear C₁-C₁₀ alkyl group or fluorinated linear C₁-C₁₀ alkyl group, preferably a linear C₁-C₄ alkyl group or a —CH₂CF₃ group

or a group of formula

in which Q³, Q⁴, Q⁵ and Q⁶ are independently from each other hydrogen atoms or methyl or ethyl groups.

Preferably the ketal or the acetal of formula (XI) or (XII) are

(E)-2-(4,8-dimethylnona-3,7-dien-1-yl)-2,5,5-trimethyl-1,3-dioxane, (E)-2,6-dimethyl-10, 10-bis(2,2,2-trifluoroethoxy)undeca-2,6-diene, (E)-2-(4,8-dimethylnon-3-en-1-yl)-2,5,5-trimethyl-1,3-dioxane, (E)-6,10-dimethyl-2,2-bis(2,2,2-trifluoro-ethoxy)undec-5-ene, (E)-2,5,5-trimethyl-2-(4,8,12-trimethyltridec-3-en-1-yl)-1,3-dioxane, (R,E)-2,5,5-trimethyl-2-(4,8,12-trimethyltridec-3-en-1-yl)-1,3-dioxane, (E)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadec-5-ene, (R,E)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadec-5-ene, (Z)-2-(4,8-dimethylnona-3,7-dien-1-yl)-2,5,5-trimethyl-1,3-dioxane, (Z)-2,6-dimethyl-10,10-bis(2,2,2-tri-fluoroethoxy)undeca-2,6-diene, (Z)-2-(4,8-dimethylnon-3-en-1-yI)-2,5,5-trimethyl-1,3-dioxane, (Z)-6,10-dimethyl-2,2-bis(2,2,2-trifluoroethoxy)undec-5-ene, (Z)-2,5,5-trimethyl-2-(4,8,12-trimethyltridec-3-en-1-yl)-1,3-dioxane, (R,Z)-2,5,5-trimethyl-2-(4,8,12-trimethyltridec-3-en-1-yl)-1,3-dioxane, 2,5,5-trimethyl-2-((3E,7E)-4,8,12-trimethyltrideca-3,7,11-trien-1-yl)-1,3-dioxane, (6E,10E)-2,6,10-trimethyl-14,14-bis(2,2,2-trifluoroethoxy)pentadeca-2,6,10-triene, 2,5,5-trimethyl-2-((3E,7E)-4,8,12-trimethyltrideca-3,7-dien-1-yl)-1,3-dioxane, (5E,9E)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadeca-5,9-diene, 2,5,5-trimethyl-2-((3Z,7E)-4,8,12-trimethyltrideca-3,7,11-trien-1-yl)-1,3-dioxane, 2,5,5-trimethyl-2-((3E,7Z)-4,8,12-trimethyltrideca-3,7,11-trien-1-yl)-1,3-dioxane, 2,5,5-trimethyl-2-((3Z,7Z)-4,8,12-trimethyltrideca-3,7,11-trien-1-y|)-1,3-dioxane, (6Z,10E)-2,6,10-trimethyl-14,14-bis(2,2,2-trifluoroethoxy)pentadeca-2,6,10-triene, (6E,10Z)-2,6,10-trimethyl-14,14-bis(2,2,2-trifluoroethoxy)pentadeca-2,6,10-triene, (6Z,10Z)-2,6,10-trimethyl-14,14-bis(2,2,2-trifluoroethoxy)pentadeca-2,6,10-triene, 2,5,5-trimethyl-2-((3Z,7E)-4,8,12-trimethyltrideca-3,7-dien-1-yl)-1,3-dioxane, 2,5,5-trimethyl-2-((3E,7Z)-4,8,12-trimethyltrideca-3,7-dien-1-yI)-1,3-dioxane, 2,5,5-trimethyl-2-((3Z,7Z)-4,8,12-trimethyltrideca-3,7-dien-1-yl)-1,3-dioxane, (5Z,9E)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadeca-5,9-diene, (5E,9Z)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadeca-5,9-diene, (5Z,9Z)-6,10,14-triniethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadeca-5,9-diene, (E)-2-(2,6-dimethylhept-1-en-1-yl)-5,5-dimethyl-1,3-dioxane, (E)-3,7-dimethyl-1,1-bis(2,2,2-trifluoroethoxy)oct-2-ene, (E)-3,7-dimethyl-1,1-bis(2,2,2-trifluoroethoxy)octa-2,6-diene, (Z)-2-(2,6-dimethylhept-1-en-1-yl)-5,5-dimethyl-1,3-dioxane, (Z)-3,7-dimethyl-1,1-bis(2,2,2-trifluoroethoxy)oct-2-ene, (Z)-3,7-dimethyl-1,1-bis(2,2,2-trifluoroethoxy)octa-2,6-diene, 2,6-dimethyl-8,8-bis(2,2,2-trifluoroethoxy)oct-2-ene, (R)-2,6-dimethyl-8,8-bis(2,2,2-trifluoroethoxy)oct-2-ene, 2-((1Z,3E)-4,8-dimethylnona-1,3,7-trien-1-yl)-2,5,5-trimethyl-1,3-dioxane, 2-((1E,3Z)-4,8-dimethylnona-1,3,7-trien-1-yl)-2,5,5-trimethyl-1,3-dioxane, 24-(1Z,3Z)-4,8-dimethylnona-1,3,7-trien-1-yl)-2,5,5-trimethyl-1,3-dioxane, (6Z,8E)-2,6-dimethyl-10,10-bis(2,2,2-trifluoroethoxy)undeca-2,6,8-triene, (6E,8Z)-2,6-dimethyl-10,10-bis(2,2,2-trifluoroethoxy)undeca-2,6,8-triene, (6Z,8Z)-2,6-dimethyl-10,10-bis(2,2,2-trifluoroethoxy)undeca-2,6,8-triene, (Z)-2,5-dimeth yl-2-(4,8,12-tri methyltridec-3-en-1-yl)-1,3-dioxane, (R,Z)-2,5-dimethyl-2-(4,8,12-trimethyltridec-3-en-1-yl)-1,3-dioxane, (Z)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadec-5-ene, (R,Z)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadec-5-ene.

Separation

In step a) the isomers having E-configuration from the isomers having Z-isomers in the mixture of isomers of compound of formula (I) or (II) or the acetal or ketal thereof are separated.

This separation of isomers in step a) can be done in different ways. A first possibility is the separation by means of chromatography.

A further and preferred way of separation is that the separation of isomers in step a) is done by distillation. The separation is possible by the fact that the isomers have different boiling points. In order to minimize thermal degradation of the isomers it is advisable to distil under reduced pressure and by means of a distillation column.

Very often the boiling points of the isomers are very similar, however, by using specific distillation techniques and equipment separation or at least enrichment of the desired isomers is nevertheless possible.

In order to optimize the purity of the isomers separated from the mixture, the distillation is made by using specific distillation techniques to ensure that impurities of other isomers are as low as possible. This particularly is also achieved in that only a part, namely the purest fractions, of the desired isomer is collected in a distillation whereas a remainder is left in the distillation flask and that the less pure fractions are either further distilled or joined to the remainder of the distillation.

The separation of the isomers having E-configuration as well as the separation of the isomers having Z-configuration can be achieved by sequential fractional distillation or by using by suitable distillation techniques or equipment. For example by using a side take-off point at a rectification column and eventually further rectification of the material collected at said side take-off, such as the technique and equipment that has been disclosed for example in EP 2 269 998 A2, particularly FIGS. 1 and 3, the entire content of which is hereby incorporated by reference.

Asymmetric Hydrogenation

In step b) the isomers having the E-configuration of compound of formula (I) or (II) or the corresponding acetal or ketal thereof are subjected to hydrogenation by molecular hydrogen in the presence of a chiral iridium complex of formula (III) having the S-configuration at the stereogenic centre indicated by *.

In step c) the isomers having the Z-configuration of compound of formula (I) or (II) or the corresponding acetal or ketal thereof are subjected to hydrogenation by molecular hydrogen in the presence of a chiral iridium complex of formula (III) having the R-configuration at the stereogenic centre indicated by *.

The steps b) and c) can be in the order first b) then c) or first c and then b) or in parallel.

In case an acetal or ketal is to be hydrogenated in step b) and/or c) it is preferred that the acetal or ketal formation is occurring between step a) and b) or c) in a step a′) formation of a ketal or acetal from a compound of formula (I) or (II).

The ketal or acetal formation has been disclosed before in detail.

In case the compound of formula (I) or (II) or an acetal or a ketal thereof have in the same molecule more than one prochiral carbon-carbon double bonds such compounds may have the same (“all Z” or “all E”) E/Z configurations or have different E/Z configurations (e.g. EZ or ZE). For the purpose of this invention, it is advisable that only those isomers of compound of formula (I) or (II) or the acetal or ketal thereof having the E-configuration at all prochiral carbon-carbon double bonds are submitted to the hydrogenation in step b); and only those isomers of compound of formula (I) or (II) or the acetal or ketal thereof having the Z-configuration at all prochiral carbon-carbon double bonds are submitted to the hydrogenation in step c). It is preferred that compounds of formula (I) or (II) or an acetal or a ketal thereof which have in the same molecule different E/Z configurations at the prochiral carbon-carbon double bonds are submitted to a step of cis/trans isomerization of said prochiral carbon-carbon double bonds. Such a cis/trans isomerization is performed in the presence of a cis/trans isomerization catalyst, particularly an organic sulphur compound, particularly a polythiol, or nitrogen monoxide. This allows that undesired isomers are converted into such isomers having all E or all Z configuration at the corresponding prochiral double bonds.

In step b) and c) the isomers having the E-configuration of compound of formula (I) or (II) or the corresponding acetal or ketal thereof are asymmetrically hydrogenated by molecular hydrogen in the presence of a chiral iridium complex of formula (III)

The complex of formula (III) is neutral, i.e. the complex consists of a complex cation of formula (III′) and anion Y as defined before.

The person skilled in the art knows that anions and cations may be dissociated.

X¹ and/or X² represent preferably hydrogen atoms, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, neopentyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantly, phenyl, benzyl, o-tolyl, m-tolyl, p-tolyl, 4-methoxyphenyl, 4-trifluoromethylphenyl, 3,5-di-tert-butylphenyl, 3,5-dimethoxyphenyl, 1-naphthyl, naphthyl, 2-furyl, ferrocenyl or a phenyl group which is substituted with one to five halogen atoms.

In case of X¹ and/or X² representing phenyl groups which are substituted with one to five halogen atoms, the phenyl groups substituted by fluorine atoms are particularly useful, i.e. C₆H₄F, C₆H₃F₂, C₆H₂F₃, C₆HF₄ or C₆F₅.

In case of X¹ and/or X² representing phenyl groups which are substituted with one to three C₁₋₄-alkyl, the phenyl groups substituted by methyl group(s) are particularly useful, particularly ortho-tolyl and para-tolyl.

Preferably both X¹ and X² represent the same substituent.

Most preferred both X¹ and X² are phenyl or ortho-tolyl groups.

It is preferred that the C₁-C₄-alkyl or alkoxy groups used in the definition of R², R³, R⁴, R⁵R⁶, R⁷, R⁸, R⁹ and R¹⁹ above are primary or secondary, preferably primary, alkyl or alkoxy groups.

A particularly suited substituent R¹ of formula (IVa) is the 9-anthryl or 1-naphthyl group.

A further particularly suited substituent R¹ of formula (IVb) is the mesityl group.

A further particularly suited substituent R¹ of formula (IVc) is the 2-naphthyl group.

Preferably R¹ is represented by phenyl (abbreviated as “Ph”) or formula (IV-1) or (IV-2) or (IV-3), particularly (IV-1) or (IV-3).

It has been found that the most preferred substituent R¹ is either 9-anthryl or phenyl.

The preferred chiral iridium complexes of formula (III) are the complexes of formulae (III-A), (III-B), (III-C), (III-D), (III-E) and (III-F).

Most preferred as chiral iridium complexes of formula (III) are the complexes of formulae (III-C) and (III-D) and (III-F), particularly the one of formula (III-C) or (III-F).

The chiral iridium complexes of formula (III) can be synthesized accordingly as described in detail in Chem. Sci., 2010, 1, 72-78 whose entire content is hereby incorporated by reference.

The iridium complex of formula (III) is chiral. The chirality at said chiral centre marked by the asterisk is either S or R. i.e. there exist two enantiomers (IIIa) and (IIIb) of the chiral complex of formula (III):

The individual enantiomers of the complex of formula (III) could be principally separated after the complexation step from a racemic mixture. However, as Chem. Sci., 2010, 1, 72-78 discloses, the synthesis of the complex of formula (III) comprises a reaction involving a non-racemic chiral alcohol. As it is known that the further reaction steps do not modify the chirality of the complex its isomeric purity (S:R-ratio) is governed therefore by the enantiomeric purity of said alcohol. As said corresponding alcohol can be obtained in a RIS ratio of more than 99% resp. lower than 1%, the complex of formula (III) can be obtained in extremely high enantiomeric purities, particularly in a R/S ratio of more than 99% resp. lower than 1%.

The chiral iridium complex is preferably used in an excess of one enantiomer.

Particularly, it is preferred that the ratio of the molar amounts of the individual enantiomers R:S of the chiral iridium complex of formula (III) is more than 90:10 or less than 10:90, preferably in the range of 100:0 to 98:2 or 0:100 to 2:98. Most preferred is that this ratio is about 100:0 resp. about 0:100. The ultimately preferred ratio is 100:0 resp. 0:100.

In one embodiment the stereogenic centre indicated by * has the R-configuration.

In another embodiment the stereogenic centre indicated by * has the S-configuration.

The hydrogenating agent is molecular hydrogen (H₂).

The amount of chiral iridium complex is preferably present during the hydrogenation in an amount in the range from 0.0001 to 5 mol-%, preferably from about 0.001 to about 2 mol-%, more preferably from about 0.001 to about 1 mol-%, most preferably from 0.001 to 0.1 mol-%, based on the amount of the compound of formula (I) or (II) or the acetal or ketal thereof.

The hydrogenation can be carried out in substance or in an inert carrier, particularly in an inert solvent, or a mixture of inert solvents. The hydrogenation is preferred carried out in substance (neat).

Preferred suitable solvents are halogenated hydrocarbons, hydrocarbons, carbonates, ethers and halogenated alcohols.

Particularly preferred solvents are hydrocarbons, fluorinated alcohols and halogenated hydrocarbons, particularly halogenated aliphatic hydrocarbons.

Preferred examples of hydrocarbons are hexane, heptane, toluene, xylene and benzene, particularly toluene and heptane.

Preferred ethers are dialkylethers. Particularly useful ethers are dialklyethers with less than 8 carbon atoms. Most preferred ether is methyl tert.-butyl ether (CH₃—O—C(CH₃)₃).

Preferred halogenated alcohols are fluorinated alcohols. A particularly preferred fluorinated alcohol is 2,2,2-trifluoroethanol.

One preferred group of halogenated hydrocarbon are halogenated aromatic compounds, particularly chlorobenzene.

Preferred examples of halogenated aliphatic hydrocarbons are mono- or polyhalogenated linear or branched or cyclic C₁ to C₁₅-alkanes. Especially preferred examples are mono- or polychlorinated or -brominated linear or branched or cyclic C₁- to C₁₅-alkanes. More preferred are mono- or polychlorinated linear or branched or cyclic C₁- to C₁₅-alkanes. Most preferred are dichloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, chloroform, and methylene bromide.

The most preferred solvent for the hydrogenation is dichloromethane.

The amount of solvent used is not very critical. However, it has been shown that the concentration of the ketone or ketal to be hydrogenated is preferably between 0.05 and 1 M, particularly between 0.2 and 0.7 M.

The hydrogenation reaction is conveniently carried out at an absolute pressure of molecular hydrogen from about 1 to about 100 bar, preferably at an absolute pressure of molecular hydrogen from about 20 to about 75 bar. The reaction temperature is conveniently between about 0 to about 100° C., preferably between about 10 to about 60° C.

The sequence of addition of the reactants and solvent is not critical.

The technique and apparatus suitable for the hydrogenation is principally known to the person skilled in the art.

By the asymmetric hydrogenation a prochiral carbon-carbon double bond is hydrogenated to form a chiral stereogenic centre at one or both of the carbon atoms.

Hydrogenated Compounds

As a result of the asymmetric hydrogenation in steps b) and c) the compound of formula (I-A) or (I-B) or an acetal or a ketal thereof is formed.

In case the carbon-carbon double bonds of compound of formula (I) or (II) or the acetals or ketals thereof is prochiral a stereogenic centre is formed by step b) and c). This stereogenic centre has the R-configuration. In case the carbon-carbon double bonds of compound of formula (I) or (II) or the acetals or ketals thereof are not prochiral no stereogenic centre has been formed by step b) and c).

Preferred compounds of formula (I-A) and (I-B) are (R)-3,7-dimethyloctanal, (R)-6,10-dimethylundecan-2-one and (6R,10R)-6,10,14-trimethylpentadecan-2-one.

In case the compound of formula (I) or (II) has been asymmetrically hydrogenated in the form of a ketal or acetal, after the asymmetric hydrogenation the asymmetrically hydrogenated ketal or acetal has preferably the formula (XV) or (XVI) or (XVII).

and wherein Q and Q¹ and Q² are as defined for formula (XI) or (XII).

Particularly the ketal or acetal of formula (XV) or (XVI) or (XVII) is selected from the group consisting of formula (XVa), (R)-2-(4,8-dimethylnonyl)-2,5,5-trimethyl-1,3-dioxane, (R)-6,10-dimethyl-2,2-bis(2,2,2-trifluoroethoxy)undecane, and (6R,10R)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadecane.

In formula (XVa) Q and Q¹ and Q² are as defined for formula (XI) or (XV).

In one embodiment the ketal or acetal of formula (XI) or (XV) are selected from the group consisting of (R)-1,1-dimethoxy-3,7-dimethyloctane, (R)-1,1-diethoxy-3,7-dimethyloctane, (R)-3,7-dimethyl-1,1-dipropoxyoctane, (R)-1,1-dibutoxy-3,7-dimethyloctane, (R)-1,1-diisobutoxy-3,7-dimethyloctane, (R)-3,7-dimethyl-1,1-bis(2,2,2-trifluoroethoxy)octane, (R)-2-(2,6-dimethylheptyl)-1,3-dioxolane, 24-(R)-2,6-dimethylheptyl)-4-methyl-1,3-dioxolane, 2-((R)-2,6-dimethylheptyl)-4,5-dimethyl-1,3-dioxolane, 24-(R)-2,6-dimethylheptyphexahydrobenzo[d]-[1,3]dioxole, (R)-2-(2,6-dimethylheptyl)-1,3-dioxane, 2-((R)-2,6-dimethylheptyl)-5-methyl-1,3-dioxane, (R)-2-(2,6-dimethylheptyl)-5,5-dimethyl-1,3-dioxane; (R)-2-(4,8-dimethylnonyl)-2,5,5-trimethyl-1,3-dioxane, (R)-6,10-dimethyl-2,2-bis(2,2,2-trifluoroethoxy)undecane and (6R,10R)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoro-ethoxy)pentadecane.

In a further embodiment the ketal or acetal of formula (XI) or (XV) are selected from the group consisting of (R)-3,7-dimethyl-1,1-bis(2,2,2-trifluoroethoxy)octane, (R)-2-(2,6-dimethylheptyl)-5,5-dimethyl-1,3-dioxane; (R)-2-(4,8-dimethylnonyl)-2,5,5-trimethyl-1,3-dioxane, (R)-6,10-dimethyl-2,2-bis(2,2,2-trifluoroethoxy)undecane and (6R,10R)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoro-ethoxy)pentadecane.

Despite the fact that the asymmetric hydrogenation of the compounds of formula (I) or (II) by means of molecular hydrogen in the presence of a chiral iridium complex, particularly those of formula (III), is already rather fast and efficient and shows high conversion rates as well as excellent selectivities, it has been observed that the asymmetric hydrogenation can even be improved when ketals or acetals of the corresponding ketones are asymmetrically hydrogenated.

In a preferred embodiment of the invention the asymmetric hydrogenation in step b) and/or step c) takes place in the presence of an additive which is selected from the group consisting of organic sulfonic acids, transition metal salts of organic sulfonic acids, metal alkoxides, aluminoxanes, alkyl aluminoxanes and B(R)_((3-v))(OZ)_(v); wherein v stands for 0, 1, 2 or 3 and R stands for F, a C₁₋₆-alkyl, a halogenated C₁₋₆-alkyl, an aryl or halogenated aryl group; and Z stands a C₁₋₆-alkyl, a halogenated C₁₋₆-alkyl, an aryl or halogenated aryl group.

Particularly suitable additives are selected from the group consisting of triflic acid, alkyl aluminoxanes, particularly methyl aluminoxane, ethyl aluminoxane, tetra alkoxy titanates. B(R)_((3-v))(OZ)_(v); particularly tri-isopropylborate and triethylborane and BF₃, preferably in the form of a BF₃ etherate.

Particularly useful as the transition metal salts of organic sulfonic acids are scandium, indium, yttrium and zirconium salts of organic sulfonic acids.

Metal alkoxides are known to the person skilled in the art. This term particularly relates to the alkoxides of the elements of the group 4 and 13 of the periodic system. It is also known to the person skilled in the art that the metal alkoxides often do not form well-defined structures. Characteristically, metal alkoxides have hydrocarbyl group bound by an oxygen atom to a metal centre. A metal alkoxide may also have different metal centres which are bridged by oxygen or oxygen containing groups, such as for example (polynuclear) aluminium oxoalkoxides.

Particularly useful as metal alkoxides are titanium alkoxides (also being called alkoxy titanates) zirconium alkoxides (also being called alkoxy zirconates) or aluminium alkoxides.

A particularly preferred class of metal alkoxide is of the type of polynuclear aluminium oxoalkoxides such as disclosed in J. Chem. Soc., Dalton Trans., 2002, 259-266 or in Organometallics 1993, 12, 2429-2431.

Alkyl aluminoxanes, are known products which are particularly useful as co-catalysts for olefin polymerizations of the Ziegler-Natta type. They are prepared by controlled hydrolysis of trialkylaluminium compound, particularly trimethylaluminium or triethylaluminium. The hydrolysis can be achieved for example by hydrated metal salts (metal salts containing crystal water).

Preferably the additive is selected from the group consisting of triflic acid, alkyl aluminoxanes, particularly methyl aluminoxane, ethyl aluminoxane, tetra alkoxy titanates. B(R)_((3-v))(OZ)_(v); particularly tri-isopropylborate and triethylborane and BF₃, preferably in the form of a BF₃ etherate.

More preferred are triflic acid, alkyl aluminoxanes, particularly methyl aluminoxane, ethyl aluminoxane, tetra alkoxy titanates, B(R)_((3-v))(OZ)_(v); particularly tri-isopropylborate and triethylborane.

Especially good results have been obtained by an additive with has been obtained from trimethylaluminoxane and 2,2,2-trifluoroethanol or from trialkylaluminium and 2,2,2-trifluoroethanol.

It has been found that the quality and speed of the asymmetric hydrogenation using molecular hydrogen in the presence of a chiral iridium complex is enhanced significantly when the above mentioned additives are used.

It has been further observed that, most significantly, the efficiency of the asymmetric hydrogenation is maximized when the above mentioned additives are used with the corresponding ketal or acetals of the compound of formula (I) or (II).

The increased efficiency has the effect that the amount of chiral iridium complex can be remarkably lowered by using an ketal or acetal of compound of formula (I) or (II) and/or addition of the mentioned additive(s), particularly in the combination with fluorinated alcohols, particularly 2,2,2-trfluoroethanol, to achieve a given yield and stereospecific hydrogenation in the asymmetric hydrogenation as compared to the corresponding asymmetric hydrogenation of the compound of formula (I) or (II) as such.

Both steps b) and c) yield to the same product, i.e. compound of formula (I-A) Or(I-B) or an acetal or a ketal thereof. Hence, it is reasonable that in an optional step d) the hydrogenated products of step b) and c) are combined.

Furthermore, in case the acetal or the ketal of compound of formula (I) or (II) has been hydrogenated in step b) and/or c), that the hydrogenated ketal or acetal is hydrolysed to the corresponding ketone or aldehyde, i.e. to compound of formula (I-A) or (I-B) in an optional step e). The hydrolysis and conditions for the hydrolysis of the hydrogenated ketal or acetal to the corresponding ketone or aldehyde are known to the person skilled in the art. Particularly suitable is the hydrolysis by means of an acid and isolation of the ketone or aldehyde, particularly by means of extraction.

In a further aspect the invention relates to a ketal of formula (XX-A)

-   -   wherein Q¹ and Q² are as defined in detail before for         formula (XI) and (XII) and wherein the double bond having dotted         lines (         ) represent either a single carbon-carbon bond or a double         carbon-carbon bond.

In a further aspect the invention relates to a ketal of formula (XX-B)

-   -   wherein Q¹ and Q² are as defined in detail before for         formula (XI) and (XII) and where a wavy line represents a         carbon-carbon bond which is linked to the adjacent carbon-carbon         double bonds so as to have said carbon-carbon double bonds         either in the Z or in the E-configuration.

In a further aspect the invention relates to an acetal of formula (XX-C)

-   -   wherein Q¹ and Q² are as defined in detail before for         formula (XI) and (XII) and wherein the double bond having dotted         lines (         ) represent either a single carbon-carbon bond or a double         carbon-carbon bond;     -   and wherein a wavy line represents a carbon-carbon bond which is         linked to an adjacent single carbon bond (         representing —) or to an adjacent carbon-carbon double bond (         representing ═) so as to have said carbon-carbon double bond         either in the Z or in the E-configuration.

In a further aspect the invention relates to an acetal of formula (XXI-A) or (XXI-B) or (XXI-C) or (XXI-D)

-   -   wherein Q stands for H or CH₃ and m and p stand independently         from each other for a value of 0 to 3 with the proviso that the         sum of m and p is 0 to 3, wherein the double bond having dotted         lines (         ) in the above formulae represents either a single carbon-carbon         bond or a double carbon-carbon bond; and     -   wherein a wavy line represents a carbon-carbon bond which is         linked to an adjacent single carbon bond (         representing —) or to an adjacent carbon-carbon double bond (         representing ═) so as to have said carbon-carbon double bond         either in the Z or in the E-configuration.

All these compounds of formula (XX-A), (XX-B), (XX-C), (XXI-A), (XXI-B), (XXI-C) or (XXI-D) are sub groups of the acetals or ketals of compound of formula (I) or (II) or acetals or ketones of the compound of formula (I-A) or (I-B) which have been shown to be very interesting starting materials or products of the process of manufacturing compound of formula (I-A) or (I-B) or an acetal or a ketal thereof described in detail before.

In a further aspect, the invention relates to a composition comprising

-   -   at least one ketal of formula (XI) or (XII) and     -   at least one chiral iridium complex of formula (III)

The ketal of formula (XI) or (XII) and chiral iridium complex of formula (III), their ratios and as well their preferred embodiments, properties and effects have been discussed in this documents already in great detail.

Compound of formula (I-A), (I-B) as well as particularly compounds of formula (XX-A), (XX-B), (XX-C), (XXI-A), (XXI-B), (XXI-C) or (XXI-D) as well as compositions comprising a ketal of formula (XI) or (XII) and a chiral iridium complex of formula (III) are interesting to be used as intermediates for the synthesis of tocopherols, vitamin K1, as well as for the synthesis of compositions in the field of flavours and fragrances or pharmaceutical products. The majority of them have a typical odour which makes them also very attractive to be used as ingredients in products of the industry of flavours and fragrances such as in perfumes.

FIGURES

In the following paragraphs some preferred embodiments of the inventions are further discussed by means of schematic FIGS. 1 to 3. This, however, is not to be understood as limiting the invention to the embodiments described here in the figures.

The FIGS. 1 to 3 show schematically an embodiment of the process of invention on 6,10-dimethylundec-5-en-2-one and 6,10-dimethylundeca-5,9-dien-2-one and 6,10,14-trimethylpentadec-5-en-2-one as examples of compounds of formula (I) and (II).

The reference signs in parentheses in the figures, such as (R-II) are used for identification purposes as described below and are not to be confused with the indication of formula such as (II) used in the rest of this document.

In FIG. 1, the process is schematically shown for the synthesis of (R)-6,10-dimethylundecan-2-one (R-II) from an E/Z mixture (E/Z-I) of 6,10-dimethylundec-5-en-2-one or 6,10-dimethylundeca-5,9-dien-2-one.

In step a) the E-isomer (E-I) (i.e. (E)-6,10-dimethylundec-5-en-2-one or (E)-6,10-dimethylundeca-5,9-dien-2-one, respectively) and the corresponding Z-isomer (Z-I) (i.e (Z)-6,10-dimethylundec-5-en-2-one or (Z)-6,10-dimethylundeca-5,9-dien-2-one, respectively) are separated from the mixture of E/Z isomers (E/Z-I). The separation in step a) is preferably done by distillation over a column.

The E-isomer (E-I) is asymmetrically hydrogenated in step b) using molecular hydrogen in the presence of the chiral iridium complex of formula (IIIa) (S-Ir-complex) having the S-configuration at the stereogenic centre indicated by * in formula (III). The Z-isomer (Z-I), on the other hand, is asymmetrically hydrogenated in step c) using molecular hydrogen in the presence of the chiral iridium complex of formula (IIIb) (R-Ir-complex) having the R-configuration at the stereogenic centre indicated by * in formula (III). Both asymmetric hydrogenation routes furnish the same product, i.e. (R)-6,10-dimethylundecan-2-one (R-II) which in step d) are combined. The double bond at position 9 of 6,10-dimethylundeca-5,9-dien-2-one is also hydrogenated during the asymmetric hydrogenation. However, as this double bond is not prochiral, no chiral centre is formed at this position during the hydrogenation.

FIG. 2 shows schematically a different example. FIG. 2 corresponds to the FIG. 1 except that the individual substances are extended by a C5 unit. In analogy, at least one isomer of the mixture (E/Z-R-III) of (R,E)-6,10,14-trimethylpentadec-5-en-2-one and (R,Z)-6,10,14-trimethylpentadec-5-en-2-one (E/Z-R-III) is separated in step a) and asymmetrically hydrogenated to (6R,10R)-6,10,14-trimethylpentadecan-2-one (R-IV) in step b) and c) and combined at the end in step d).

FIG. 3) shows schematically the preferred process using a ketal or acetal during the hydrogenation process. In step a) the E-isomer (E-1) (i.e. (E)-6,10-dimethylundec-5-en-2-one or (E)-6,10-dimethylundeca-5,9-dien-2-one, respectively) and the corresponding Z-isomer (Z-1) (i.e (Z)-6,10-dimethylundec-5-en-2-one or (Z)-6,10-dimethylundeca-5,9-dien-2-one, respectively) are separated from the mixture of E/Z isomers (E/Z-I). The separation in step a) is preferably done by distillation over a column.

E-isomer (E-1) and the Z-isomer (Z-1) are converted into the corresponding ketal, i.e. into the ketal of the E-isomer (E-IK) or the Z-isomer (Z-IK) by using an to alcohol (in FIG. 3 2,2,2-trifluoroethanol is shown) in the presence of an acid.

The ketal of the E-isomer (E-IK) is asymmetrically hydrogenated in step b) using molecular hydrogen in the presence of the chiral iridium complex of formula (IIIa) (S-Ir-complex) having the S-configuration at the stereogenic centre indicated by * in formula (III). The ketal of the Z-isomer (Z-IK), on the other hand, is asymmetrically hydrogenated in step c) using molecular hydrogen in the presence of the chiral iridium complex of formula (IIIb) (R-Ir-complex) having the R-configuration at the stereogenic centre indicated by * in formula (III). Both asymmetric hydrogenation routes furnish the same product, i.e. the ketal of (R)-6,10-dimethylundecan-2-one (R-/IK) which after acidic hydrolysis into (R)-6,10-dimethylundecan-2-one (R-II) in step e) are combined in step d). However, the FIG. 3 shows also possibility for a different route at the end in dashed lines. After the hydrogenation in step b) and c) the formed ketal of the ketal of (R)-6,10-dimethylundecan-2-one (R-IIK) are first combined in step d) and then hydrolysed by acid into the (R)-6,10-dimethylundecan-2-one (R-II). The later of these variants is the preferred one.

Examples

The present invention is further illustrated by the following experiments.

Analytical Methods GC Determination of E/Z-ratio and/or purity of 6,10-dimethylundec-5-en-2-one (DHGA), (R)-6,10-dimethylundecan-2-one (THGA) and (R)-6,10,14-trimethylpentadec-5-en-2-one (R-THFA)

Agilent 6850, column DB-5HT (30 m, 0.25 mm diameter, 0.10 μm film thickness), 107 kPa helium carrier gas). The samples were injected as solutions in hexane, split ratio 300:1, injector temperature 200° C., detector temperature 350° C. Oven temperature program: 100° C. (8 min), 10° C./min to 200° C. (1 min), 20° C./min to 220° C. (4 min), runtime 24 min.

GC Determination of purity of (6R,10R)-6,10,14-trimethylpentadecan-2-one

Agilent 6850, column DB-5HT (30 m, 0.25 mm diameter, 0.10 μm film thickness), 115 kPa helium carrier gas). The samples were injected as solutions in hexane, split ratio 300:1, injector temperature 200° C., detector temperature 350° C. Oven temperature program: 120° C. (5 min), 14° C./min to 260° C. (2 min), 20° C./min to 280° C. (4 min), runtime 22 min.

GC Determination of purity of (3RS,7R,11R)-3,7,11,15-tetramethylhexadec-1-en-3-ol ((R,R)-Isophytol)

Agilent 6850 instrument equipped with FID. Agilent DB-5 column (30 m, 0.32 mm diameter, 0.25 μm film thickness) with 25 psi molecular hydrogen carrier gas. The samples were injected as solutions in acetonitrile with a split ratio of 50:1. Injector temperature: 250° C., detector temperature: 350° C. Oven temperature program: 100° C., 4° C./min to 250° C.

GC Determination of E/Z-ratio and/or purity of 6,10,14-trimethylpentadeca-5,9-dien-2-one 6,10,14-trimethylpentadeca-5,9,13-trien-2-one, 6,10-dimethylundeca-5,9-dien-2-one and ketals

Agilent 6850 instrument, column Agilent DB-5 (123-5032E, 30 m×0.32 mm, film 0.25 μm), the samples were injected as solutions in acetonitrile, split ratio 50:1, injector 250° C., detector 350° C. Oven temperature program: 100° C., 4° C./min until 250° C., 37.5 min total runtime.

Retention times (t_(R)): min. (5E,9E)-6,10,14-trimethylpentadeca-5,9,13-trien-2-one 22.2 (EE-FA) EE-FA-DM decomp.² EE-FA-tfe 23.1, pc¹ (5Z,9Z)-6,10,14-trimethylpentadeca-5,9,13-trien-2-one 21.0 (ZZ-FA) ZZ-FA-DM 23.0, pc¹ ZZ-FA-neo 27.9 (5E,9E)-6,10,14-trimethylpentadeca-5,9-dien-2-one 21.2 (EE-DHFA) EE-DHFA-DM 24.6, pc¹ EE-DHFA-neo 29.5 EE-DHFA-tfe 22.4 (5Z,9Z)-6,10,14-trimethylpentadeca-5,9-dien-2-one 20.0 (ZZ-DHFA) ZZ-DHFA-DM 23.0, pc¹ ZZ-DHFA-neo 27.9 (E)-6,10-dimethylundeca-5,9-dien-2-one (E-GA) 11.0 E-GA-DM 14.8 E-GA-neo 20.5 E-GA-tfe 13.2, pc¹ (Z)-6,10-dimethylundeca-5,9-dien-2-one (Z-GA) 10.6 Z-GA-DM 14.0, pc¹ Z-GA-neo 19.5 E-DHGA-DM 14.1, pc¹ E-DHGA-neo 19.6, pc¹ E-DHGA-tfe 12.5 Z-DHGA-DM 13.0, pc¹ Z-DHGA-neo 18.5, pc¹ R,E-THFA-DM 24.2, pc¹ R,E-THFA-neo 29.1 R,Z-THFA-DM 23.1, pc¹ R,Z-THFA-neo 27.9 R-THGA-DM 13.1 R-THGA-neo 18.9 R-THGA-tfe 11.8 RR-C18-DM decomp.² RR-C18-neo 28.5 RR-C18-tfe 21.4 ¹pc = partial decomposition ²decomp. = decomposition during GC analysis

Analysis of the Asymmetrically Hydrogenated Reaction Products

The corresponding dimethyl, ethylene glycol, neopentyl and bis(trifluoroethyl) ketals were hydrolyzed to the ketones in the presence of aqueous acid and analyzed for conversion and their stereoisomer ratio using the following methods for ketones.

The conversion of the hydrogenation reaction was determined by gas chromatography using an achiral column.

Method for Conversion:

Agilent 7890A GC equipped with FID. Agilent HP-5 column (30 m, 0.32 mm diameter, 0.25 μm film thickness) with 25 psi molecular hydrogen carrier gas. The samples were injected as solutions in dichloromethane with a split ratio of 10:1. Injector temperature: 250° C., detector temperature: 300° C. Oven temperature program: 50° C. (2 min) then 15° C./min to 300° C., hold 5 min.

For the determination of the isomer ratio, the hydrogenated ketones can be reacted with either (+)-diisopropyl-0,0′-bis(trimethylsilyI)-L-tartrate or ( )-diisopropyl-0,0′-bis(trimethylsilyl)-D-tartrate in the presence of trimethylsilyl triflate [Si(CH₃)₃(OSO₂CF₃)] to form the diastereomeric ketals as described in A. Knierzinger, W. Walther, B. Weber, R. K. Müller, T. Netscher, Helv. Chin. Acta 1990, 73, 1087-1107. The ketals can be analysed by gas chromatography using an achiral column to determine the isomer ratios. For the hydrogenated ketone 6,10-dimethylundecan-2-one, either D-(−)- or L-(+)-diisopropyltartrate can be used. For 6,10,14-trimethylpentadecan-2-one, L-(+)-diisopropyltartrate can be used to measure the quantity of the (6R,10R)-isomer that was present. D-(−)-diisopropyltartrate can be used to determine the amount of the (6S,10S)-isomer. Thus the selectivity of the stereoselective hydrogenation can be determined indirectly.

Method for Determination of Isomers:

Agilent 6890N GC with FID. Agilent CP-Sil88 for FAME column (60 m, 0.25 mm diameter, 0.20 μm film thickness) with 16 psi molecular hydrogen carrier gas. The samples were injected as solutions in ethyl acetate with a split ratio of 5:1. Injector temperature: 250° C., FID detector temperature: 250° C. Oven temperature program: 165° C. (isothermal, 240 min)

The Ir complexes indicated in the following experiments are prepared according to the disclosure in Chem. Sci., 2010, 1, 72-78.

Experiment E1-1 Separation of E/Z isomer mixtures of 6,10-dimethylundec-5-en-2-one (step a)

7.02 kg of 6,10-dimethylundec-5-en-2-one was prepared according to example 10 of DE 1 193 490 and was analysed by the GC method given above to be a 57%/43% mixture of (E)-6,10-dimethylundec-5-en-2-one and (Z)-6,10-dimethylundec-5-en-2-one (99% purity).

The mixture was distilled using separation equipment consisting of a still (volume: 9 litre) with a falling film evaporator, a rectifying column (70 mm inner diameter, height 5 m). The column was equipped with a very efficient structured packing (Sulzer). The mixture was rectified at a top pressure of approx. 5 mbar and at a column top temperature in the range from 105 to 112° C. and a bottom temperature in the still of about 125° C. The reflux ratio was adjusted to 20.

Fractions containing (Z)-6,10-dimethylundec-5-en-2-one (content of Z-isomer=99%, E-isomer <1%) as well as fractions containing (E)-6,10-dimethylundec-5-en-2-one (content of E-isomer 97%, Z-isomer <3%) were collected. At the end (E)-6,10-dimethylundec-5-en-2-one (content of E-isomer=99.5%, Z-isomer=0.5%) was found left in the still.

Experiment E1-2 Asymmetric hydrogenations of 6,10-dimethylundec-5-en-2-one (step b/c)

Both isomers (E)-6,10-dimethylundec-5-en-2-one (“E-DHGA”) (E/Z=99.5/0.5) and (Z)-6,10-dimethylundec-5-en-2-one (“Z-DHGA”) (Z/E=99/1) were hydrogenated asymmetrically, separate from each other in the following manner:

A 2 L autoclave was charged with 70 g (0.353 mol) of the specific isomer, 700 mL of 2,2,2-trifluoroethanol and a solution of the chiral iridium complex of formula (III-F) having the chirality given in table 1 at the centre indicated by * in said formula (570 mg, 0.356 mmol, 0.1 mol %) in anhydrous dichloromethane (10 g). The autoclave was closed and a pressure of 50 bar of molecular hydrogen was applied. The reaction mixture was heated to 30° C. whilst stirring for 2 hours. Afterwards the pressure was released and the solvent was removed. The product formed is (R)-6,10-dimethylundecan-2-one. The conversion as well as the amount of isomers formed is determined as indicated above and the results are given in table 1.

The products of the two separate asymmetric hydrogenations have been combined (Step d).

TABLE 1 Asymmetric hydrogenation of E-DHGA and Z-DHGA. 1 2 E-DHGA Z-DHGA Formula of Ir complex III-F III-F Configuration of chiral Ir complex at * S R Amount of chiral Ir complex [mol-%] 0.1 0.1 Conversion >98% >99% (R)-6,10-dimethylundecan-2-one [%] 95.8  93.3  (S)-6,10-dimethylundecan-2-one [%] 4.2 6.7

Experiment E2-1 Separation of E/Z isomer mixtures of (R,Z)-6,10,14-trimethyl-pentadec-5-en-2-one (step a)

The mixture of (R,E)-6,10,14-trimethylpentadec-5-en-2-one and (R,Z)-6,10,14-trimethylpentadec-5-en-2-one [1.94 kg, 36% (R,Z)-6,10,14-trimethylpentadec-5-en-2-one and 49% (R,E)-6,10,14-trimethylpentadec-5-en-2-one) was fractionated using the separation equipment consisting of a still (volume: 9 litre) with a falling film evaporator, a rectifying column (70 mm inner diameter, height 5 m). The column was equipped with a very efficient structured packing (Sulzer). The rectification process was operated at a top pressure of approx. 2 mbar and at a column top temperature varied in the range from 95 to 122° C. and the bottom temperature in the still was 165° C. The reflux ratio was adjusted to 20. Fractionation of the distillate stream furnished fractions containing (R,Z)-6,10,14-trimethylpentadec-5-en-2-one (content of Z-isomer=97%). At the end (R,E)-6,10,14-trimethylpentadec-5-en-2-one was found left in the still (content of E-isomer=94%). Both isomers were further purified by fractionation and furnished fractions of both E-isomer and Z-isomer each with a purity of 99.5%)

Experiment E2-2 Asymmetric hydrogenations of (R,E)-6,10,14-trimethylpentadec-5-en-2-one and (R,Z)-6,10,14-trimethylpentadec-5-en-2-one (step b/c)

Both isomers (R,E)-6,10,14-trimethylpentadec-5-en-2-one) (“R,E-THFA”) (E/Z=99.5/0.5, R/S=92/8) and (R,Z)-6,10,14-trimethylpentadec-5-en-2-one (“R,Z-THFA”) (Z/E=99.5/0.5, R/S=92/8) were hydrogenated asymmetrically, separate from each other in the following manner:

-   -   A 125 mL autoclave was charged with 7.0 g (26 mmol) of the         specific isomer, 50 mL of 2,2,2-trifluoroethanol and a solution         of the chiral iridium complex of formula (III-F) having the         chirality given in table 3 at the centre indicated by * in said         formula (42 mg, 0.026 mmol, 0.1 mol %) in anhydrous         dichloromethane (4 g). The autoclave was closed and a pressure         of 50 bar of molecular hydrogen was applied. The reaction         mixture was heated to 30° C. whilst stirring for 16 hours.         Afterwards the pressure was released and the solvent removed.         The product formed is         (6R,10R)-6,10,14-trimethylpentadecan-2-one. The conversion as         well as the amount of isomers formed is given in table 2.

The products of the two separate asymmetric hydrogenations have been combined (step d).

In a further experiment 0.25 mmol of (R,E)-6,10,14-trimethylpentadec-5-en-2-one) (“R,E-THFA”) and 1 mol-%, of the Ir complex of the formula (III-0) and 1.25 ml of absolute (dry) dichloromethane were placed in an autoclave. The autoclave was closed and a pressure of 50 bar of hydrogen was applied. The reaction solution was stirred at room temperature for 14 hours. Afterwards the pressure was released and the solvent removed. For the determination of the conversion the crude product was analysed by achiral gas chromatography without any further purification. The amount for the isomers has been determined using the above method and given in table 2.

TABLE 2 Asymmetric hydrogenation of R,E-THFA and R,Z-THFA. 3 4 5 R,Z- R,E- R,E- THFA THFA THFA Formula of Ir-complex III-F III-F III-D Configuration of chiral Ir-complex R S S Amount of chiral Ir complex [mol-%] 0.1 0.1 1   Conversion >99% >99% 100% (6R,10R)-6,10,14-trimethylpentadecan-2-one 87.0  88.4 97.0  [%] (6S,10R)-6,10,14-trimethylpentadecan-2-one 5.3 3.7 1.8 [%] (6R,10S)-6,10,14-trimethylpentadecan-2-one 7.7 7.9  1.2* [%] (6S,10S)-6,10,14-trimethylpentadecan-2-one 0.0 0.0 [%] *(6R,10S) and (6S,10S) isomers determined as sum.

Experiment E3 Separation of EE/ZZ/(EZ+ZE) isomer mixtures of 6,10,14-trimethylpentadeca-5,9,13-then-2-one (step a)

A commercial sample of 6,10,14-trimethylpentadeca-5,9,13-then-2-one being a mixture of (5E,9E)-I (5E,9Z)-I (5Z,9E)-I and (5Z,9Z)-6,10,14-trimethylpentadeca-5,9,13-trien-2-one has separated by fractional distillation into a low boiling fraction of the (5Z,9Z)-isomer and a high boiling fraction of (5E,9E) isomer and a mid boiling fraction containing both (5E,9Z)- and I(5Z,9E)-isomers.

The high boiling EE-isomer has been isolated as having a content of 97.9% of (5E,9E)-6,10,14-trimethylpentadeca-5,9,13-then-2-one, 0% (5Z,9Z)-6,10,14-trimethylpentadeca-5,9,13-trien-2-one and 0.5% of the sum of (5E,9Z)- and (5Z,9E)-6,10,14-trimethylpentadeca-5,9,13-trien-2-one (total of 98.4% 6,10,14-trimethylpentadeca-5,9,13-trien-2-one isomers, measured by GC (labelled in the following as “EE-FA”).

The low boiling ZZ-isomer has been isolated as having a content of 88.6% of (5Z,9Z)-6,10,14-trimethylpentadeca-5,9,13-trien-2-one, 0% (5E,9E)-6,10,14-trimethylpentadeca-5,9,13-trien-2-one and 4.0% of the sum of (5E,9Z)- and (5Z,9E)-6,10,14-trimethylpentadeca-5,9,13-trien-2-one (total of 92.6% 6,10,14-trimethylpentadeca-5,9,13-trien-2-one isomers, measured by GC) (labelled in the following as “ZZ-FA”).

Experiment E4 Separation of EE/ZZ/(EZ+ZE) isomer mixtures of 6,10,14-tri methyl pentadeca-5,9-di en-2-one (step a)

A sample of 6,10,14-trimethylpentadeca-5,9-dien-2-one being a mixture of (5E,9E)-I (5E,9Z)-I (5Z,9E)-I and (5Z,9Z)-6,10,14-trimethylpentadeca-5,9-dien-2-one was separated by fractioned distillation into a low boiling fraction of (5Z,9Z)-isomer (labelled in the following as “ZZ-DHFA”) and a high boiling fraction of (5E,9E) isomer (labelled in the following as “EE-DHFA”) and a mid boiling fraction containing both (5E,9Z)- and (5Z,9E)-isomer (labelled in the following as “EZ/ZE-DHFA”).

The mid boiling mixture EZ/ZE-DHFA of EZ- and ZE-isomers has been isolated as having a content of 93.3% of the sum of (5E,9Z)- and (5Z,9E)-6,10,14-trimethylpentadeca-5,9-dien-2-one, 3.0% (5E,9E)-6,10,14-trimethylpentadeca-5,9-dien-2-one and 1.0% of (5Z,9Z)-6,10,14-trimethylpentadeca-5,9-dien-2-one (total of 97.3% 6,10,14-trimethylpentadeca-5,9-dien-2-one isomers, measured by GC).

Experiment E5 Preparation of Ketals a) Preparation of Dimethyl Ketals

The corresponding ketone as indicated in tables 3a or 3b was added to trimethyl orthoformate (50.8 mL, 49.2 g, 451 mmol, 2.65 eq.) and cooled to 5° C. Sulfuric acid (96%, 32.3 mg, 0.29 mmol, 0.2 mol %) in MeOH (16 mL) was added within 5 min. Subsequently, the reaction was heated to reflux (65° C. IT) for 3 h. After cooling, thin layer chromatography (TLC) analysis indicated full conversion. NaOMe (0.24 mL of a 25% solution in MeOH) was added to neutralize the acid. The mixture was concentrated in vacuo and subsequently diluted with hexane (50 mL). The developed precipitate was filtered off and the filtrate was concentrated. The crude product was purified by distillation, furnishing the desired dimethyl ketal.

The characterization of the ketal is given in detail hereafter.

TABLE 3a Preparation of dimethyl ketals of 6,10-dimethylundeca-5,9- dien-2-one and 6,10-dimethylundec-5-en-2-one. E-GA-DM Z-GA-DM E-DHGA-DM Z-DHGA-DM Ketone (E)-6,10-di- (Z)-6,10-di- (E)-6,10-dimethyl- (Z)-6,10-dimethyl- methylundeca- methylundeca- undec-5-en-2-one undec-5-en-2-one 5,9-dien-2-one 5,9-dien-2-one Ketal (E)-10,10-dimethoxy- (Z)-10,10-dimethoxy- (E)-2,2-dimethoxy- (Z)-2,2-dimethoxy- 2,6-dimethyl- 2,6-dimethyl- 6,10-dimethyl- 6,10-dimethyl- undeca-2,6-diene undeca-2,6-diene undec-5-ene undec-5-ene Yield [%] 87 73 91 98 E/Z 99.4/0.6 1.6/98.4 95.4/4.6 0.4/99.6

TABLE 3b Preparation of dimethyl ketals of 6,10,14-trimethylpentadeca-5,9,13- trien-2-one and 6,10,14-trimethylpentadeca-5,9-dien-2-one. EE-FA-DM EE-DHFA-DM ZZ-DHFA-DM Ketone (5E,9E)-6,10,14-trimethyl- (5E,9E)-6,10,14-tri- (5Z,9Z)-6,10,14-tri- pentadeca-5,9,13-trien-2- methylpentadeca-5,9- methylpentadeca-5,9- one dien-2-one dien-2-one Ketal (6E,10E)-14,14-dimethoxy- (5E,9E)-2,2-dimethoxy- (5Z,9Z)-2,2-dimethoxy- 2,6,10-trimethyl- 6,10,14-trimethyl- 6,10,14-trimethyl- pentadeca-2,6,10-triene pentadeca-5,9-diene pentadeca-5,9-diene Yield [%] 95 90 56 Purity¹ 95.1 99.0 96.5 ¹Purity determined by quantitative ¹H-NMR.

Characterization Data: (E)-10,10-dimethoxy-2,6-dimethylundeca-2,6-diene (E-GA-DM)

¹H NMR (300 MHz, CDCl₃): δ 1.26 (s, 3H), 1.58 (s, 3H), 1.60 (s, 3H), superimposed by 1.60-1.65 (m, 2H), 1.66 (br s, 3H), 1.92-2.09 (m, 6H), 3.17 (s, 6H), 5.02-5.14 (m, 2H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 15.9 (1C), 17.6 (1C), 20.8 (1C), 22.8 (1C), 25.6 (1C), 26.6 (1C), 36.4 (1C), 39.6 (1C), 47.9 (2C), 101.4 (1C), 123.8 (1C), 124.2 (1C), 131.2/1C), 135.1 (1C) ppm.

MS (EI, m/z): 240 (M⁺, <1), 225.3 [(M-CH₃)⁺, 1], 209.3 [(M-CH₃O)⁺, 20], 193.3 (8), 176.2 (18), 161.2 (16), 139.2 (20), 123.2 (14), 107.2 (75), 89.2 (100), 69.2 (65), 41.1 (56).

IR (cm⁻¹): 2928 (m), 2857 (w), 2828 (w), 1670 (w), 1452 (m), 1376 (s), 1345 (w), 1302 (w), 1262 (w), 1222 (w), 1196 (m), 1172 (m), 1123 (s), 1102 (s), 1053 (s), 985 (w), 929 (w), 854 (s), 744 (w), 619 (w).

(Z)-10,10-dimethoxy-2,6-dimethylundeca-2,6-diene (Z-GA-DM)

¹H NMR (300 MHz, CDCl3): δ 1.27 (s, 3H), 1.56-1.65 (m, 5H), 1.68 (br. s, 6H), 1.96-2.09 (m, 6H), 3.17 (s, 6H), 5.11 (t, J=7.2 Hz, 2H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 17.6 (1C), 20.9 (1C), 22.7 (1C), 23.3 (1C), 25.7 (1C), 26.6 (1C), 31.9 (1C), 36.7 (1C), 48.0 (2C), 101.4 (1C), 124.2 (1C), 124.6 (1C), 131.5 (1C), 135.4 (1C) ppm.

MS (EI, m/z): No GC-MS was obtained due to decomposition on the column.

IR (cm⁻¹): 2943 (m), 2858 (w), 2828 (w), 1451 (m), 1376 (m), 1348 (w), 1301 (w), 1261 (w), 1197 (m), 1172 (m), 1153 (w), 1120 (s), 1098 (m), 1053 (s), 929 (w), 854 (m), 833 (m), 745 (w), 622 (w).

(E)-2,2-dimethoxy-6,10-dimethylundec-5-ene (E-DHGA-DM)

¹H NMR (300 MHz, CDCl₃): δ 0.83 (d, J=6.6 Hz, 6H), 1.02-1.13 (m, 2H), 1.24 (s, 3H), 1.27-1.39 (m, 2H), 1.49 (tqq, J=6.4, 6.4, 6.4 Hz, 1H), superimposed by 1.53-1.63 (m, 2H), superimposed by 1.56 (s, 3H), 1.87-2.03 (m, 4H), 3.13 (s, 6H), 5.07 (tq, J=7.0, 1.4 Hz, 1H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 16.1 (1C), 21.2 (1C), 23.0 (2C), 23.2 (1C), 26.0 (1C), 28.2 (1C), 36.9 (1C), 39.0 (1C), 40.2 (1C), 48.3 (2C), 101.8 (1C), 124.0 (1C), 135.9 (1C) ppm.

MS (EI, m/z): No GC-MS was obtained due to decomposition on the column.

IR (cm⁻¹): 2953 (s), 2931 (s), 2870 (m), 2828 (m), 2108 (w), 1668 (w), 1460 (m), 1377 (s), 1367 (m), 1345 (w), 1301 (w), 1262 (m), 1221 (m), 1198 (m), 1172 (s), 1119 (s), 1100 (s), 1077 (s), 1053 (s), 967 (w), 927 (w), 854 (w), 796 (w), 739 (w), 620 (w).

(Z)-2,2-di meth oxv-6,10-dimethylundec-5-ene (Z-DHGA-DM)

¹H NMR (300 MHz, CDCl₃): δ 0.88 (d, J=6.6 Hz, 6H), 1.12-1.21 (m, 2H), 1.28 (s, 3H), 1.32-1.43 (m, 2H), 1.53 (dspt, J=6.6, 6.6 Hz, 1H), 1.57-1.66 (m, 2H), 1.68 (q, J=1.1 Hz, 3H), 1.94-2.06 (m, 4H), 3.18 (s, 6H), 5.10 (t, J=6.8 Hz, 1H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 20.9 (1C), 22.6 (2C), 22.7 (1C), 23.3 (1C), 25.8 (1C), 27.9 (1C), 31.9 (1C), 36.8 (1C), 38.9 (1C), 48.0 (2C), 101.5 (1C), 124.3 (1C), 135.9 (1C) ppm.

MS (EI, m/z): No GC-MS was obtained due to decomposition on the column.

IR (cm⁻¹): 2953 (s), 2870 (w), 2828 (w), 1461 (w), 1376 (m), 1301 (w), 1261 (w), 1205 (m), 1172 (m), 1119 (m), 1097 (m), 1074 (m), 1053 (s), 1022 (w), 927 (w), 854 (m), 738 (w), 621 (w).

(5E,9E)-6,10,14-trimethyl-pentadeca-5,9,13-trien-2-one (EE-FA-DM)

¹H-NMR (300.1 MHz, CDCl₃): δ=1.28 (s, 2-CH₃), 1.56-1.70 (m, 4 CH₃+CH₂), 1.92-2.12 (m, 10H), 3.18 (s, 2 OCH₃), 5.05-5.17 (m, 3H_(olefin)).

¹³C-NMR (75.5 MHz, CDCl₃): δ=16.0 (2C), 17.7, 20.9, 22.8, 25.7, 26.6, 26.8, 36.5, 39.67, 39.72, 48.0 (2 OCH₃), 101.5 (C-2), 123.8 and 124.2 and 124.4 (3C_(olefin)), 131.3 and 135.0 and 135.3 (3 C_(olefin)).

IR (ATR, cm⁻¹): 2924s, 2856w, 2828w, 1668m, 1450s, 1376s, 1346w, 1302m, 1261m, 1222m, 1196m, 1172m, 1153w, 1123s, 1053s, 985w, 929w, 854s, 744m, 620w

MS (m/z): 308 (M⁺, 0.1%), 293 [(M-15)⁺, 0.2], 276 [/(M-CH₃OH)⁺, 6], 244 [(M-2CH₃OH)⁺, 4], 207 [(M-CH₃OH—O₅H₉)⁺, 11], 175 [(M-2CH₃OH—O₅H₉)⁺, 19], 107 [(M-2CH₃OH-2C₅H₉+H)⁺, 71], 69 (C₅H₉ ⁺, 100).

(5E,9E)-6,10,14-trimethylpentadeca-5,9-dien-2-one (EE-DHFA-DM)

¹H NMR (300 MHz, CDCl₃): δ0.87 (d, J=6.6 Hz, 6H), 1.06-1.17 (m, 2H), 1.28 (s, 3H), 1.31-1.42 (m, 2H), 1.53 (tqq, J=6.6, 6.6, 6.6 Hz, 1H), superimposed by 1.58 (s, 3H), superimposed by 1.58-1.65 (m, 2H), superimposed by 1.62 (s, 3H), 1.90-2.11 (m, 8H), 3.18 (s, 6H), 5.06-5.15 (m, 2H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 16.3 (1C), 16.4 (1C), 21.3 (1C), 23.0 (2C), 23.3 (1 C), 26.2 (1C), 27.0 (1C), 28.3 (1C), 36.9 (1C), 39.0 (1C), 40.1 (1C), 40.3 (1C), 48.4 (2C), 101.9 (1C), 124.25 (1C), 124.31 (1C), 135.66 (1C), 135.71 (1C) ppm.

MS (EI, m/z): No GC-MS was obtained due to decomposition on the column.

IR (cm⁻¹): 2953 (m), 2930 (m), 2870 (m), 2828 (w), 1668 (w), 1457 (m), 1377 (m), 1345 (w), 1302 (w), 1262 (m), 1222 (m), 1196 (m), 1172 (m) 1123 (s), 1054 (s), 929 (w), 854 (s), 739 (w), 620 (w).

(5Z,9Z)-6,10,14-trimethylpentadeca-5,9-dien-2-one (ZZ-DHFA-DM)

¹H NMR (300 MHz, CDCl₃): δ 0.88 (d, J=6.6 Hz, 6H), 1.11-1.21 (m, 2H), 1.28 (s, 3H), 1.30-1.43 (m, 2H), 1.54 (qq, J=6.6 Hz, 1H), superimposed by 1.57-1.66 (m, 2H), 1.67 (br s, 3H), 1.69 (q, J=1.3 Hz, 3H), 1.94-2.10 (m, 8H), 3.18 (s, 6H), 5.12 (t, J=6.4 Hz, 2H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 20.9 (1C), 22.3 (1C), 22.6 (1C), 22.7 (1C), 23.39 (1C), 23.40 (1C), 25.8 (1C), 26.3 (1C), 27.9 (1C), 31.9 (1C), 32.2 (1C), 36.7 (1C), 38.9 (1C), 48.0 (2C), 101.4 (1C), 124.6 (1C), 124.7 (1C), 135.4 (1C), 135.8 (1C) ppm.

MS (EI, m/z): No GC-MS was obtained due to decomposition on the column.

IR (cm⁻¹): 2953 (m), 2870 (m), 2828 (w), 1454 (m), 137 (m), 1302 (w), 1261 (m), 1201 (m), 1172 (m), 1152 (m), 1098 (m), 1054 (s), 854 (s), 749 (w), 622 (w).

b) Preparation of Ethylene Glycol Ketals

Under nitrogen, a reaction vessel was charged with glycol (112 mL, 125 g, 2.1 mol), p-toluenesulfonic acid monohydrate (0.150 g, 0.5774 mmol) and 0.5 mol either of (E)-6,10-dimethylundec-5-en-2-one or (Z)-6,10-dimethylundec-5-en-2-one. The mixture was allowed to stir at ambient temperature for 5 hours at reduced pressure (0.39 mbar). While maintaining the low pressure, the temperature was slowly increased to 40° C. At conversion of larger than 95% of the ketone, the temperature was further increased allowing a gentle distillation of glycol and continued until a conversion of more than 99% was achieved.

At room temperature, the product was extracted by a solution of triethylamine in heptane (2 mL triethylamine/L heptane). The glycol phase was separated and the heptane layer was washed with a NaHCO₃ solution in water. Separation of the heptane phase, drying over anhydrous Na₂SO₄, filtration and removal of the solvent in vacuo gave the crude ketal. The ketal was further purified by means of distillation. The corresponding ketal was identified by ¹H-NMR.

TABLE 3c Preparation of ethylene glycol ketals. E-DHGA-en Z-DHGA-en Ketone (E)-6,10-dimethylundec-5- (Z)-6,10-dimethylundec-5- en-2-one en-2-one Ketal (E)-2-(4,8-dimethylnon-3-en- (Z)-2-(4,8-dimethylnon-3-en- 1-yl)-2-methyl-1,3-dioxolane 1-yl)-2-methyl-1,3-dioxolane Yield [%] 88 87

Characterization Data (E)-2-(4,8-dimethylnon-3-en-1-yl)-2-methvl-1,3-dioxolane (E-DHGA-en)

¹H NMR (300 MHz, CDCl₃) δ 5.12 (t, 1H), 3.95 (m, 4H), 2.2-2 (m, 2H), 1.94 (t, 2H), 1.8-1.3 (m, 11H), 1.2-1.0 (m, 2H), 0.87 (d, 6H) ppm.

(Z)-2-(4,8-dimethylnon-3-en-1-yl)-2-methyl-1,3-dioxolane (Z-DHGA-en)

¹H NMR (300 MHz, CDCl₃) δ 5.12 (t, 1H), 3.94 (m, 4H), 2.15-1.9 (m, 4H), 1.7-1.45 (m, 6H), 1.44-1.27 (m, 5H), 1.23-1.08 (m, 2H), 0.88 (d, 6H) ppm.

c) Preparation of Neopentyl Glycol Ketals

The ketone (90.7 mmol) indicated in tables 3d or 3e, 2,2-dimethyl-1,3-propanediol (neopentylglycol, 32.4 g, 283 mmol, 3.4 eq.) and p-toluene sulfonic acid monohydrate (60 mg, 0.31 mmol, 0.3 mol %) were suspended in toluene (300 mL). The reaction was heated to 90° C. upon which a homogeneous solution formed. Subsequently, at 75° C., vacuum was applied cautiously (first 63 mbar, then 24 mbar) in order to slowly distill toluene off (approx. 100 mL over 4 h). After 4 h, thin layer chromatography (TLC) analysis indicated full conversion of the ketone. The reaction was allowed to cool to room temperature and diluted with heptane (300 mL) upon which excess neopentylglycol precipitated. The precipitate was filtered off (17.4 g wet). The filtrate was treated with Et₃N (1 mL), subsequently washed with aqueous NaHCO₃ solution (2.4% w/w, 2×300 mL), dried over MgSO₄ and concentrated in vacuo. The crude product was purified by distillation, furnishing the desired neopentyl ketal. The characterization of the ketal is given in detail hereafter.

TABLE 3d Preparation of neopentyl glycol ketals. E-GA-neo Z-GA-neo E-DHGA-neo Z-DHGA-neo Ketone (E)-6,10-di- (Z)-6,10-di- (E)-6,10-dimethyl- (Z)-6,10-dimethyl- methylundeca- methylundeca- undec-5-en-2-one undec-5-en-2-one 5,9-dien-2-one 5,9-dien-2-one Ketal (E)-2-(4,8-di- (Z)-2-(4,8-di- (E)-2-(4,8-di- (Z)-2-(4,8-di- methylnona-3,7- methylnona-3,7- methylnon-3-en-1- methylnon-3-en-1- dien-1-yl)-2,5,5- dien-1-yl)-2,5,5- yl)-2,5,5-trimethyl- yl)-2,5,5-trimethyl- trimethyl-1,3- trimethyl-1,3- 1,3-dioxane 1,3-dioxane dioxane dioxane Yield [%] 78 87 89 84 E/Z 99.4/0.6 1.7/98.3 95.3/4.7 1.6/98.4

TABLE 3e Preparation of neopentyl glycol ketals of 6,10,14-trimethylpentadeca- 5,9-dien-2-one. EE-DHFA-neo ZZ-DHFA-neo Ketone (5E,9E)-6,10,14-trimethyl- (5Z,9Z)-6,10,14- pentadeca-5,9-dien-2-one trimethylpentadeca-5,9-dien- 2-one Ketal 2,5,5-trimethyl-2-((3E,7E)- 2,5,5-trimethyl-2-((3Z,7Z)- 4,8,12-trimethyltrideca-3,7- 4,8,12-trimethyltrideca-3,7-dien- dien-1-yl)-1,3-dioxane 1-yl)-1,3-dioxane Yield [%] 81 70 EE/(ZE + 97.0/3.0/0.0 0.0/2.5/97.5 ZE)/ZZ E/Z

Characterization Data: (E)-2-(4,8-dimethylnona-3,7-dien-1-yl)-2,5,5-trimethyl-1,3-dioxane (E-GA-neo)

¹H NMR (300 MHz, CDCl₃): δ 0.92 (s, 3H), 0.99 (s, 3H), 1.37 (s, 3H), 1.59 (s, 3H), 1.61 (s, 3H), 1.67 (s, 3H), 1.68-1.75 (m, 2H), 1.94-2.15 (m, 6H), AB signal (δ_(A)=3.46, δ_(B)=3.52, J_(AB)=11.3 Hz, 4H), 5.05-5.17 (m, 2H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 15.9 (1C), 17.6 (1C), 20.8 (1C), 22.0 (1C), 22.6 (1C), 22.7 (1C), 25.6 (1C), 26.7 (1C), 29.9 (1C), 37.3 (1C), 39.6 (1C), 70.3 (2C), 98.8 (1C), 124.1 (1C), 124.3 (1C), 131.2 (1C), 135.1 (1C) ppm.

MS (EI, m/z): 280 (M⁺, 3), 265 [(M-CH₃)⁺, 14], 176 (21), 129 [(C₇H₁₃O₂)⁺, 100], 69 (63), 43 (43).

IR (cm⁻¹): 2954 (m), 2925 (m), 2858 (m), 2731 (w), 1720 (w), 1669 (w), 1473 (w), 1450 (m), 1394 (m), 1372 (m), 1349 (w), 1306 (w), 1271 (w), 1249 (m), 1211 (m), 1186 (m), 1123 (s), 1088 (s), 1043 (m), 1021 (m), 984 (w), 950 (w), 925 (w), 907 (w), 862 (m), 837 (w), 792 (w), 742 (w), 677 (w), 667 (w).

(Z)-2-(4,8-dimethylnona-3,7-dien-1-yl)-2,5,5-trimethyl-1,3-dioxane (Z-GA-neo)

¹H NMR (300 MHz, CDCl₃): δ 0.91 (s, 3H), 0.97 (s, 3H), 1.35 (s, 3H), 1.60 (s, 3H), 1.64-1.74 (m, 5H) superimposed by 1.67 (br s, 3H), 1.99-2.18 (m, 6H), AB signal (δ_(A)=3.44, δ_(B)=3.51, J_(AB)=11.3 Hz, 4H), 5.07-5.16 (m, 2H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 17.5 (1C), 20.9 (1C), 21.3 (1C), 21.9 (1C), 22.5 (1C), 22.6 (1C), 23.3U C), 25.7 (1C), 26.6 (1C), 29.9 (1C), 31.8 (1C), 37.5 (1C), 70.3 (1C), 98.7 (1C), 124.3 (1C), 124.9 (1C), 131.4 (1C), 135.2 (1C) ppm.

MS (EI, m/z): 280 (M⁺, 3), 265 [(M-CH₃)⁺, 13], 176 (19), 129 [(C₇H₁₃O₂)⁺, 100], 107 (15), 69 (62), 43 (39).

IR (cm⁻¹): 2954 (m), 2927 (m), 2858 (m), 2729 (w), 1721 (w), 1671 (w), 1473 (m), 1450 (m), 1394 (m), 1374 (m), 1349 (w), 1315 (w), 1271 (m), 1249 (m), 1211 (m), 1187 (m), 1149 (w), 1120 (s), 1086 (s), 1043 (m), 1021 (m), 985 (w), 951 (m), 925 (w), 907 (m), 857 (m), 833 (m), 792 (w), 743 (w), 677 (w), 667 (w).

(E)-2-(4,8-dimethylnon-3-en-1-yl)-2,5,5-trimethyl-1,3-dioxane (E-DHGA-neo)

¹H NMR (300 MHz, CDCl₃): δ 0.87 (d, J=6.6 Hz, 6H), 0.93 (s, 3H), 1.00 (s, 3H), 1.06-1.22 (m, 2H), 1.31-1.43 (m, 2H) superimposed by 1.38 (s, 3H), 1.53 (tqq, J=6.6, 6.6, 6.6 Hz, 1H), 1.61 (br s, 3H), 1.65-1.77 (m, 2H), 1.94 (t, J=7.5 Hz, 2H), 2.05-2.17 (m, 2H), AB signal (bp, =3.46, δ_(B)=3.54, J_(AB)=11.4 Hz, 4H), 5.13 (tq, J=7.1, 1.1 Hz, 1H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 15.8 (1C), 20.9 (1C), 22.0 (1C), 22.59 (1C), 22.63 (2C), 22.7 (1C), 25.7 (1C), 27.9 (1C), 29.9 (1C), 37.3 (1C), 38.6 (1C), 39.9 (1C), 70.3 (2C), 98.8 (1C), 123.8 (1C), 135.6 (1C) ppm.

MS (EI, m/z): 282 (M⁺, 5), 267 [(M-CH₃)⁺, 10), 129 (100), 95 (14), 69 (36), 43 (32).

IR (cm⁻¹): 2953 (s), 2929 (m), 2868 (m), 1720 (w), 1468 (m), 1394 (m), 1381 (m), 1368 (m), 1349 (w), 1306 (w), 1270 (w), 1250 (m), 1211 (m), 1187 (w), 1118 (s), 1087 (s), 1066 (m), 1044 (m), 1022 (m), 950 (m), 925 (w), 907 (m), 862 (m), 791 (w), 739 (w), 677 (w), 666 (w).

(Z)-2-(4,8-dimethylnon-3-en-1-yl)-2,5,5-trimethyl-1,3-dioxane (Z-DHGA-neo)

¹H NMR (300 MHz, CDCl₃): δ 0.87 (d, J=6.6 Hz, 6H), 0.93 (s, 3H), 0.97 (s, 3H), 1.10-1.20 (m, 2H), 1.34-1.41 (m, 3H) superimposed by 1.36 (s, 3H), 1.53 (tqq, J=6.6, 6.6, 6.6 Hz, 1H), 1.64-1.75 (m, 2H) superimposed by 1.67 (q, J=1.5 Hz, 3H), 1.95-2.15 (m, 4H), AB signal (δ_(A)=3.46, δ_(B)=3.51, J_(AB)=11.1 Hz, 4H), 5.12 (br t, J=7.2 Hz, 1H)

¹³C NMR (75 MHz, CDCl₃): δ 21.1 (1C), 22.0 (1C), 22.61 (3C), 22.65 (1C), 23.4 (1C), 25.7 (1C), 27.9 (1C), 29.9 (1C), 31.9 (1C), 37.2 (1C), 38.8 (1C), 70.3 (2C), 98.8 (1C), 124.6 (1C), 135.8 (1C) ppm.

MS (EI, m/z): 282 (M⁺, 6), 267 [(M-CH₃)⁺, 11), 129 (100), 95 (14), 69 (35), 43 (32).

IR (cm⁻¹): 2953 (s), 2867 (m), 1722 (w), 1468 (m), 1394 (m), 1368 (m), 1349 (w), 1306 (w), 1270 (w), 1250 (m), 1211 (m), 1189 (w), 1116 (s), 1086 (s), 1043 (m), 1022 (m), 951 (m), 925 (w), 907 (m), 856 (m), 792 (w), 739 (w), 677 (w), 667 (w).

2,5,5-trimethyl-2-((3E,7E)-4,8,12-trimethyltrideca-3,7-dien-1-yl)-1,3-dioxane (EE-DHFA-neo)

¹H NMR (300 MHz, CDCl₃): δ 0.86 (d, J=6.6 Hz, 6H), 0.92 (s, 3H), 0.99 (s, 3H), 1.05-1.22 (m, 2H), 1.37 (s, 3H), superimposed by 1.31-1.42 (m, 2H), 1.52 (tqq, J=6.6, 6.6, 6.6 Hz, 1H), 1.57 (s, 3H), 1.61 (s, 3H), 1.67-1.76 (m, 2H), 1.88-2.16 (m, 8H), AB signal (δ_(A), =3.45, δ_(B)=3.52, J_(AB)=11.3 Hz, 4H), 5.05-5.17 (m, 2H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 15.85 (1C), 15.92 (1C), 20.9 (1C), 22.0 (1C), 22.55 (1C), 22.62 (2C), 22.68 (1C), 25.7 (1C), 26.5 (1C), 27.8 (1C), 29.9 (1C), 37.3 (1C), 38.6 (1C), 39.7 (1C), 39.9 (1C), 70.3 (2C), 98.8 (1C), 123.9 (1C), 124.1 (1C), 135.1 (1C), 135.2 (1C) ppm.

MS (EI, m/z): 350 (M⁺, 4), 335 [(M-CH₃)⁺, 11), 246 (10), 206 (10), 161 (9), 129 (100), 107 (13), 69 (38), 43 (32).

IR (cm⁻¹): 2953 (s), 2928 (s), 2867 (m), 1462 (m), 1394 (m), 1382 (m), 1368 (m), 1305 (w), 1271 (w), 1249 (m), 1211 (m), 1187 (m), 1123 (s), 1087 (s), 1043 (m), 1021 (m), 950 (w), 925 (w), 907 (w), 862 (m) 791 (w), 739 (w), 678 (w).

2,5,5-trimethyl-2-((3E,7E)-4,8,12-trimethyltrideca-3,7-dien-1-yl)-1,3-dioxane (ZZ-DHFA-neo)

¹H NMR (300 MHz, CDCl₃): δ 0.87 (d, J=6.8 Hz, 6H), 0.92 (s, 3H), 0.98 (s, 3H), 1.10-1.21 (m, 2H), 1.29-1.42 (m, 2H), superimposed by 1.36 (s, 3H), 1.53 (qqt, J=6.7, 6.7, 6.7 Hz, 1H), 1.66 (br. s, 3H), 1.68 (q, J=1.4 Hz, 3H), 1.67-1.75 (m, 2H), 1.99 (t, J=7.7 Hz, 2H), 2.02-2.16 (m, 6H), AB signal (δ_(A)=3.45, δ_(B)=3.52, J_(AB)=11.5 Hz, 4H), 5.02-5.22 (m, 2H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 20.9 (1C), 21.9 (1C), 22.6 (3C), 22.7 (1C), 23.38 (1C), 23.42 (1C), 25.8 (1C), 26.3 (1C), 27.9 (1C), 29.9 (1C), 31.9 (1C), 32.1 (1C), 37.4 (1C), 38.9 (1C), 70.3 (2C), 98.8 (1C), 124.7 (1C), 125.0 (1C), 135.2 (1C), 135.6 (1C) ppm.

MS (EI, m/z): 350 (M⁺, 5), 335 [(M-CH₃)⁺, 10), 246 (8), 206 (8), 151 (7), 129 (100), 107 (10), 69 (35), 43 (27).

IR (cm⁻¹): 2953 (s), 2867 (m), 1452 (m), 1394 (w), 1372 (m), 1315 (w), 1271 (w), 1249 (m), 1211 (m), 1189 (w), 1119 (s), 1087 (s), 1043 (m), 1021 (m), 951 (w), 925 (w), 907 (w), 856 (m) 792 (w), 737 (w), 668 (w).

d) Preparation of Bis(trifluoroethyl) Ketals

A 250 mL three-necked flask with stir bar was dried under high vacuum (heat gun at 250° C.), then allowed to cool, flushed with argon and charged with 1,1,1 trifluoroethanol (TFE) (40 mL) under argon. The flask was cooled with an ice-bath while trimethylaluminum (2 M in heptane, 20.0 mL, 40.0 mmol, 1.95 eq.) was added dropwise within 60 min, keeping the temperature below 22° C. The two-phase (TFE/heptane) mixture became clear again after a few minutes and was allowed to stir for an additional 20 min at room temperature. 20.7 mmol of the dimethyl ketal of the corresponding ketone as indicated in tables 3f or 3g, being prepared as shown above, was added dropwise within 5 min at room temperature. After 1.5 h, GC analysis indicated full conversion of starting material. The reaction was quenched with a half-saturated solution of potassium sodium tartrate in water (100 mL), stirred for 2 h at room temperature and finally diluted with n-hexane (200 mL). The organic phase was separated, extracted with n-hexane (2×100 mL), dried over MgSO₄ and concentrated. The crude product was purified by column chromatography (neutral aluminium oxide, eluent: n-hexane). The characterization of the ketal is given in detail hereafter.

TABLE 3f Preparation of bis(trifluoroethyl) ketals of 6,10-dimethylundeca-5,9- dien-2-one and 6,10-dimethylundec-5-en-2-one. E-GA-tfe E-DHGA-tfe Dimethylketal E-GA-DM E-DHGA-DM (reactant) Ketal (E)-2,6-dimethyl- (E)-6,10-dimethyl- 10,10-bis(2,2,2- 2,2-bis(2,2,2- trifluoroethoxy)undeca- trifluoroethoxy)undec- 2,6-diene 5-ene Yield [%] 85 74 E/Z 99.4/0.6 95.0/5.0

TABLE 3g Preparation of bis(trifluoroethyl) ketals of (5E,9E)-6,10,14-trimethyl- pentadeca-5,9,13-trien-2-one and (5E,9E)-6,10,14-trimethylpenta- deca-5,9-dien-2-one. EE-FA-tfe EE-DHFA-tfe Dimethylketal (6E,10E)-14,14-dimethoxy- (5E,9E)-2,2-dimethoxy-6,10,14- (reactant) 2,6,10-trimethylpentadeca- trimethylpentadeca-5,9-diene 2,6,10-triene Ketal (6E,10E)-2,6,10-trimethyl- (5E,9E)-6,10,14-trimethyl-2,2- 14,14-bis(2,2,2-trifluoroethoxy)- bis(2,2,2-trifluoroethoxy)penta- pentadeca-2,6,10-triene deca-5,9-diene Yield [%] 71 83 EE/(ZE + ZE + ZZ) 99/1 95/5

Characterization Data (E)-2,6-dimethyl-10,10-bis(2,2,2-trifluoroethoxy)undeca-2,6-diene (E-GA-ffe)

¹H NMR (300 MHz, CDCl₃): δ 1.41 (s, 3H), 1.62 (br s, 6H), 1.67-1.76 (m, 2H), superimposed by 1.69 (q, J=0.9 Hz, 3H), 1.93-2.15 (m, 6H), 3.73-3.97 (m, 4H), 5.02-5.18 (m, 2H) ppm.

¹³C NMR (150 MHz, CDCl₃): δ 15.9 (1C), 17.6 (1C), 21.3 (1C), 22.6 (1C), 25.7 (1C), 26.6 (1C), 36.9 (1C), 39.6 (1C), 59.3 (q, J_(C,F)=35.0 Hz, 2C), 103.4 (1C), 124.0 (q, J_(C,F)=275.0 Hz, 2C), 122.7 (1C), 124.1 (1C), 131.5 (1C), 136.2 (1C) ppm.

MS (EI, m/z): 361 [(M-CH₃)⁺, 1], 276 [(M-TFE)⁺, 15], 225 [(CF₃CH₂O)₂C—CH₃)⁺, 86], 207 (20), 153 (18), 136 (58), 107 (80), 69 (100), 41 (40).

IR (cm⁻¹): 2927 (w), 2859 (w), 1459 (w), 1419 (w), 1385 (w), 1281 (s), 1223 (w), 1156 (s), 1133 (s), 1081 (s), 971 (s), 889 (m), 860 (w), 845 (w), 678 (w), 663 (w).

(E)-6,10-dimethyl-2,2-bis(2,2,2-trifluoroethoxy)undec-5-ene (E-DHGA-tfe)

¹H NMR (600 MHz, CDCl₃): δ 0.88 (d, J=6.8 Hz, 6H), 1.11-1.17 (m, 2H), 1.35-1.40 (m, 2H), 1.41 (s, 3H), 1.54 (qqt, J=6.7, 6.7, 6.7 Hz, 1H), 1.61 (br s, 3H), 1.69-1.73 (m, 2H), 1.95 (t, J=7.7 Hz, 2H), 2.03-2.09 (m, 2H), 3.78-3.91 (m, 4H), 5.09 (tq, J=7.1, 1.3 Hz, 1H) ppm.

¹³C NMR (151 MHz, CDCl₃): δ 14.1 (1C), 15.8 (1C), 21.3 (1C), 22.56 (1C), 22.61 (1C), 25.6 (1C), 27.9 (1C), 37.0 (1C), 38.6 (1C), 39.8 (1C), 59.2 (q, J_(C,F)=35.0 Hz, 2C), 103.4 (1C), 124.0 (q, J_(C,F)=277.0 Hz, 2C), 122.4 (1C), 136.7 (1C) ppm.

MS (EI, m/z): 363 [(M-CH₃)⁺, 1], 278 [(M-TFE)⁺, 22], 225 [(CF₃CH₂O)₂C—CH₃)⁺, 60], 193 (100), 153 (13), 127 (11), 83 (CF₃CH₂ ⁺, 25), 69 (13), 43 (17).

IR (cm⁻¹): 2956 (w), 2933 (w), 2872 (w), 1462 (w), 1419 (w), 1385 (w), 1368 (w), 1281 (s), 1223 (w), 1156 (s), 1134 (s), 1081 (s), 971 (s), 889 (m), 860 (w), 845 (w), 679 (w), 663 (m).

(6E,10E)-2,6,10-trimethyl-14,14-bis(2,2,2-trifluoroethoxy)pentadeca-2,6,10-triene (EE-FA-tfe)

¹H NMR (300 MHz, CDCl₃): δ 1.41 (s, 3H), 1.61 (br s, 6H), 1.63 (br s, 3H), 1.67-1.75 (m, 2H), superimposed by 1.69 (br q, J=0.9 Hz, 3H), 1.93-2.16 (m, 10H), 3.74-3.95 (m, 4H), 5.11 (br t, J=6.5 Hz, 3H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 15.94 (1C), 15.98 (1C), 17.6 (1C), 21.3 (1C), 22.6 (1C), 25.6 (1C), 26.5 (1C), 26.8 (1C), 37.0 (1C), 39.6 (1C), 39.7 (1C), 59.3 (q, J_(C,F)=34.9 Hz, 2C), 103.4 (1C), 124.0 (q, J_(C,F)=275.8 Hz, 2C), 122.7 (1C), 124.0 (1C), 124.3 (1C), 131.3 (1C), 135.1 (1C), 136.2 (1C) ppm.

MS (EI, m/z): 444 (M⁺, 5), 429 [(M-CH₃)⁺, 1], 344 [(M-TFE)⁺, 4], 225 [(CF₃CH₂O)₂C—CH₃)⁺, 54], 175 (33), 136 (28), 107 (48), 81 (53), 69 (100), 41 (34).

IR (cm⁻¹): 2922 (w), 2858 (w), 1457 (w), 1419 (w), 1385 (w), 1282 (s), 1223 (w), 1157 (s), 1133 (s), 1111 (m), 1081 (s), 971 (s), 889 (m), 860 (w), 845 (w), 678 (w), 663 (m).

(5E,9E)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadeca-5,9-diene (EE-DHFA-tfe)

¹H NMR (300 MHz, CDCl₃): δ 0.88 (d, J=6.6 Hz, 6H), 1.08-1.20 (m, 2H), 1.32-1.44 (m, 2H), superimposed by 1.41 (s, 3H), 1.54 (tqq, J=6.6, 6.6, 6.6 Hz, 1H), 1.60 (br s, 3H), 1.63 (br s, 3H), 1.67-1.76 (m, 2H), 1.89-2.17 (m, 8H), 3.73-3.97 (m, 4H), 5.04-5.17 (m, 2H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 15.89 (1C), 15.95 (1C), 21.4 (1C), 22.60 (1C), 22.61 (2C), 25.8 (1C), 26.5 (1C), 27.9 (1C), 37.0 (1C), 38.6 (1C), 39.7 (1C), 39.9 (1C), 59.3 (q, J_(C,F)=35.5 Hz, 2C), 103.4 (1C), 124.0 (q, J_(C,F)=276.0 Hz, 2C), 122.7 (1C), 123.7 (1C), 135.5 (1C), 136.2 (1C) ppm.

MS (EI, m/z): 431 [(M-CH₃)⁺, 1], 346 [(M-TFE)⁺, 13], 262 (9), 225 [(CF₃CH₂O)₂C—CH₃)⁺, 93], 206 (43), 153 (17), 127 (24), 107 (45), 83 (CF₃CH₂ ⁺, 100), 69 (51), 55 (43), 43 (28).

IR (cm⁻¹): 2955 (w), 2931 (w), 2871 (w), 1462 (w), 1419 (w), 1385 (m), 1282 (s), 1223 (w), 1157 (s), 1133 (s), 1080 (s), 971 (s), 889 (m), 860 (w), 845 (w), 679 (w), 663 (m).

Experiment E6 Asymmetric Hydrogenations of Ketals (Step b/c)

The ketals and acetals were asymmetrically hydrogenated in the following manner:

An autoclave vessel was charged under nitrogen with chiral iridium complex of formula as indicated in tables 4a-k having the configuration at the chiral centre marked by * as indicated in tables 4a-k, the ketal or acetal (conc.) as indicated in tables 4a-k, solvent as indicated in tables 4a-k. The reaction vessel was closed and pressurized with molecular hydrogen to the pressure (pH₂) indicated in tables 4a-k. The reaction mixture was stirred at room temperature for the time (t) as indicated in tables 4a-k under hydrogen. Then the pressure was released and the assay yield and the stereoisomer distribution of the fully hydrogenated product was determined. The catalyst loading (S/C\ is defined as mmol ketal or acetal (“substrate”)/mmol chiral iridium complex.

The characterization of the hydrogenated ketals/acetals is given hereafter.

TABLE 4a Asymmetric hydrogenation of different ketals of E-6,10-dimethyl- undeca-5,9-dien-2-one (E-GA). 6 7 8 9 Ketal/ketone E-GA E-GA-DM E-GA-neo E-GA-neo Formula of Ir complex III-F III-F III-F III-F Configuration of chiral Ir (S) (S) (S) (S) complex at * Amount of chiral Ir complex 0.5 0.5 0.5 0.5 [mol-%] Solvent¹ DCM TFE DCM TFE Hydrogenated ketal/ketone R-THGA R-THGA-DM R-THGA-neo R-THGA-neo Conversion [%] 100 >99 >99 >99 Isomer-Distribution^(2,3) (R) [%] 96.5 95.3 97.5 98.4 (S) [%] 3.5 4.7 2.5 1.6 Conditions: 0.5 mmol ketal, 4 g solvent, pressure p(H₂) = 30 bar, 16 h stirring at room temperature. ¹TFE = 2,2,2-trifluoroethanol; DCM = dichloromethane ²(R) stands for the R-isomer, (S) stands for the S-isomer of the corresponding ketal of 6,10-dimethylundecan-2-one ³is determined as ketone after hydrolysis of the ketal

TABLE 4b Asymmetric hydrogenation of different ketals of Z-6,10-dimethyl- undeca-5,9-dien-2-one (Z-GA). 10 11 12 13 Ketal Z-GA-DM Z-GA-DM Z-GA-neo Z-GA-neo Formula of Ir complex III-F III-F III-F III-F Configuration of chiral Ir (R) (R) (R) (R) complex at * Amount of chiral Ir 0.5 0.25 0.25 0.25 complex [mol-%] Solvent¹ DCM TFE DCM TFE Hydrogenated ketal R-THGA- R-THGA- R-THGA- R-THGA- DM DM neo neo Conversion [%] >99 >99 >99 >99 Isomer-Distribution^(2,3) (R) [%] 98.2 98.5 97.9 98.6 (S) [%] 1.8 1.5 2.1 1.4 ¹TFE = 2,2,2-trifluoroethanol; DCM = dichloromethane ²(R) stands for the R-isomer, (S) stands for the S-isomer of the corresponding ketal of 6,10-dimethylundecan-2-one ³is determined as ketone after hydrolysis of the ketal

TABLE 4c Asymmetric hydrogenation of different ketals of E-DHGA. 14 15 16 17 Ketal E-DHGA- E-DHGA- E-DHGA- E-DHGA- DM DM neo tfe Formula of Ir complex III-F III-F III-F III-F Configuration of chiral Ir (S) (S) (S) (S) complex at * Amount of chiral Ir 0.25 0.5 0.25 0.5 complex [mol-%] Solvent¹ DCM TFE DCM TFE Hydrogenated ketal R-THGA- R-THGA- R-THGA- R-THGA- DM DM neo tfe Conversion [%] >99 >99 >99 >99 Isomer-Distribution^(2,3) (R) [%] 93.8 94.3 94.7 94.8 (S) [%] 6.2 5.7 5.3 5.2 Conditions: 0.5 mmol ketal, 4 g solvent, pressure p(H₂) = 30 bar, 16 h stirring at room temperature. ¹TFE = 2,2,2-trifluoroethanol; DCM = dichloromethane ²(R) stands for the R-isomer, (S) stands for the S-isomer of the corresponding ketal of 6,10-dimethylundecan-2-one ³is determined as ketone after hydrolysis of the ketal

TABLE 4d Asymmetric hydrogenation of different ketals of Z-DHGA. 18 19 20 21 Ketal Z-DHGA- Z-DHGA- Z-DHGA- Z-DHGA- DM DM neo neo Formula of Ir complex III-F III-F III-F III-F Configuration of chiral Ir (R) (R) (R) (R) complex at * Amount of chiral Ir 0.25 0.5 0.5 0.5 complex [mol-%] Solvent¹ DCM TFE DCM TFE Hydrogenated ketal R-THGA- R-THGA- R-THGA- R-THGA- DM DM neo neo Conversion [%] >99 >99 >99 >99 Isomer-Distribution^(2,3) (R) [%] 99.2 99.4 97.8 98.0 (S) [%] 0.8 0.6 2.2 2.0 ¹TFE = 2,2,2-trifluoroethanol; DCM = dichloromethane ²(R) stands for the R-isomer, (S) stands for the S-isomer of the corresponding ketal of 6,10-dimethylundecan-2-one ³is determined as ketone after hydrolysis of the ketal

TABLE 4e Asymmetric hydrogenation of different ketals of E,E-FA. 22 23 24 Ketal to be hydrogenated E,E-FA-DM E,E-FA-DM E,E-FA-tfe Formula of Ir-complex III-F III-F III-F Configuration of chiral (S) (S) (S) Ir-complex at * Amount of chiral Ir complex 0.25 0.25 0.5 [mol-%] Solvent¹ DCM TFE TFE Conversion [%] >99 >99 >99 Isomer-Distribution^(2,3) (RR) [%] 97.1 96.4 96.5 ((SS) + (RS)) [%] 1.3 1.3 1.5 (SR) [%] 1.6 2.3 2.0 Conditions: 0.5 mmol ketal, 4 g solvent, pressure p(H₂) = 30 bar, 16 h stirring at room temperature ¹TFE = 2,2,2-trifluoroethanol; DCM = dichloromethane ²(SS) stands for the (6S,10S)-isomer, (RR) stands for the (6R,10R)-isomer, (SR) stands for the (6S,10R)-isomer, (RS) stands for the (6R,10S)-isomer of the corresponding ketal of 6,10,14-trimethylpentadecan-2-one ³is determined as ketone after hydrolysis of the ketal

TABLE 4f Asymmetric hydrogenation of different ketals of E,E-DHFA and ZZ-DHFA. 25 26 27 28 29 Ketal to be E,E- E,E- E,E- Z,Z- Z,Z- hydrogenated DHFA-DM DHFA-neo DHFA-neo DHFA-DM DHFA-DM Formula of Ir-complex III-F III-F III-F III-F III-F Configuration of chiral (S) (S) (S) (R) (R) Ir-complex at * Amount of chiral Ir 0.25 0.5 0.5 0.5 0.5 complex [mol-%] Solvent¹ DCM DCM TFE DCM TFE Conversion [%] >99 >99 >99 >99 >99 Isomer-Distribution^(2,3) (RR) [%] 93.0 94.5 92.8 96.8 96.8 ((SS) + (RS)) [%] 5.5 5.5 5.9 1.4 1.6 (SR) [%] 1.5 0.0 1.3 1.7 1.6 Conditions: 0.5 mmol ketal, 4 g solvent, pressure p(H₂) = 30 bar, 16 h stirring at room temperature ¹TFE = 2,2,2-trifluoroethanol; DCM = dichloromethane ²(SS) stands for the (6S,10S)-isomer, (RR) stands for the (6R,10R)-isomer, (SR) stands for the (6S,10R)-isomer, (RS) stands for the (6R,10S)-isomer of the corresponding ketal of 6,10,14-trimethylpentadecan-2-one ³is determined as ketone after hydrolysis of the ketal

TABLE 4g Asymmetric hydrogenation of different ketals of (R,E)-6,10,14-tri- methylpentadec-5-en-2-one leading to (6R,10R)-6,10,14-trimethyl- pentadecan-2-one. 30 31 32 Ketal to be hydrogenated R-E-THFA- R-E-THFA- R-E-THFA- DM DM neo Formula of Ir complex III-F III-F III-F Configuration of chiral Ir (S) (S) (S) complex at * Amount of chiral Ir complex 0.25 0.25 0.5 [mol-%] Solvent¹ DCM TFE DCM Conversion [%] >99 >99 >99 Isomer-Distribution^(2,3) (RR) [%] 90.0 88.7 90.6 ((SS) + (RS)) [%] 8.0 8.7 9.4 (SR) [%] 2.0 2.6 0.0 Conditions: 0.5 mmol ketal, 4 g solvent, pressure p(H₂) = 30 bar, 16 h stirring at room temperature ¹TFE = 2,2,2-trifluoroethanol; DCM = dichloromethane ²(SS) stands for the (6S,10S)-isomer, (RR) stands for the (6R,10R)-isomer, (SR) stands for the (6S,10R)-isomer, (RS) stands for the (6R,10S)-isomer of the corresponding ketal of 6,10,14-trimethyl-pentadecan-2-one ³is determined as ketone after hydrolysis of the ketal

TABLE 4h Asymmetric hydrogenation of different ketals of (R,Z)-6,10,14-tri- methylpentadec-5-en-2-one leading to (6R,10R)-6,10,14-trimethyl- pentadecan-2-one. 33 34 35 36 Ketal to be hydrogenated R-Z- R-Z- R-Z- R-Z- THFA- THFA- THFA- THFA- DM DM neo neo Formula of Ir complex III-F III-F III-F III-F Configuration of chiral Ir complex (R) (R) (R) (R) at * Amount of chiral Ir complex 0.5 0.5 0.5 0.5 [mol-%] Solvent¹ DCM TFE DCM TFE Conversion [%] >99 >99 >99 >99 Isomer-Distribution^(2,3) (RR) [%] 86.3 87.4 86.8 85.5 ((SS) + (RS)) [%] 8.2 7.5 8.2 9.4 (SR) [%] 5.5 5.1 5.0 5.1 Conditions: 0.5 mmol ketal, 4 g solvent, pressure p(H₂) = 30 bar, 16 h stirring at room temperature ¹TFE = 2,2,2-trifluoroethanol; DCM = dichloromethane ²(SS) stands for the (6S,10S)-isomer, (RR) stands for the (6R,10R)-isomer, (SR) stands for the (6S,10R)-isomer, (RS) stands for the (6R,10S)-isomer of the corresponding ketal of 6,10,14-trimethyl-pentadecan-2-one ³is determined as ketone after hydrolysis of the ketal.

TABLE 4i Hydrogenation of E-DHGA and of E-DHGA-en. The effect of ketalization. 37 38 Ketone to be hydrogenated E-DHGA Ketal to be hydrogenated E-DHGA-en Formula of Ir complex III-F III-F Configuration of chiral Ir complex at * (R) (R) conc.¹ [mol/L] 1.0 0.9 pH₂ [bar] 50 50 t [h] 20 20 S/C 10′000 10′000 Solvent TFE TFE Assay yield [area-%] 1 97 Isomer-Distribution^(3,4) (R) [%] n.d.² 2.2 (S) [%] n.d.² 97.8 ¹conc. = mol ketone or ketal/L solvent ²n.d. = not determined (due to low assay yield) ³(R) stands for the R-isomer, (S) stands for the S-isomer of the ethylene glycol ketal of 6,10-dimethylundecan-2-one ⁴is determined as ketone after hydrolysis of the ketal

TABLE 4j Hydrogenation of Z-DHGA and of Z-DHGA-en and of Z-DHGA-neo. The effect of ketalization. 39 40 41 42 Ketone to be Z-DHGA hydrogenated Ketal to be hydrogenated Z-DHGA- Z-DHGA- Z-DHGA- en en neo Formula of Ir complex III-F III-F III-F III-F Configuration of chiral (R) (R) (R) (R) Ir complex at * conc.¹ [mol/L] 1.0 0.2 0.2 0.2 pH₂ [bar] 50 25 25 25 t [h] 20 15 15 24 S/C 5′000 5′000 10′000 10′000 Solvent DCM DCM DCM DCM Assay yield [area-%] 1 84 39 22 Isomer-Distribution^(3,4) (R) [%] n.d.² 98.6 98.4 95 (S) [%] n.d.² 1.4 1.6 5 ¹conc. = mol ketone or ketal/L solvent (DCM = dichloromethane) ²n.d. = not determined (due to low assay yield) ³(R) stands for the R-isomer, (S) stands for the S-isomer of the ethylene glycol ketal of 6,10-dimethylundecan-2-one ⁴is determined as ketone after hydrolysis of the ketal.

TABLE 4k Hydrogenation of EE-FA and of FA-en. The effect of ketalization. 43 44 45 46 47 48 49 Ketone to be hydro- EE-FA EE-FA EE-FA genated Ketal to be hydro- EE- EE- EE- EE- genated FA-en FA-en FA-en FA-en Formula of Ir III-F III-F III-F III-F III-F III-F III-F complex Configuration of (R) (R) (R) (R) (R) (R) (R) chiral Ir complex at * conc.¹ [mol/L] 0.2 0.2 0.2 0.2 0.2 0.2 0.2 pH₂ [bar] 50 25 25 25 25 25 50 t [h] 21 21 24 24 24 24 20 S/C 500 1′000 2′000 5′000 10′000 2′000 2′000 Solvent DCM DCM DCM DCM DCM TFE TFE Assay yield [area- 96 27 98 37 1 56 97 %] Isomer-Distribution^(3,4) (SS) [%] n.d.² n.d.² 96.3 96.3 n.d.² 94.4 96.5 ((RR) + (SR)) [%] n.d.² n.d.² 1.5 1.6 n.d.² 1.7 1.7 (RS) [%] n.d.² n.d.² 2.2 2.1 n.d.² 3.9 1.8 ¹conc. = mol ketone or ketal/L solvent (DCM = dichloromethane) ²n.d. = not determined ³(SS) stands for the (6S,10S)-isomer, (RR) stands for the (6R,10R)-isomer, (SR) stands for the (6S,10R)-isomer, (RS) stands for the (6R,10S)-isomer of the ethylene glycol ketal of 6,10,14-trimethyl-pentadecan-2-one ⁴is determined as ketone after hydrolysis of the ketal.

(R)-2,2-dimethoxy-6,10-dimethylundecane (R-THGA-DM)

¹H NMR (300 MHz, CDCl₃): δ 0.848 (d, J=6.6 Hz, 3H) superimposed by 0.852 (d, J=6.6 Hz, 6H), 1.01-1.41 (m, 11H) superimposed by 1.25 (s, 3H), 1.44-1.61 (m, 3H), 3.16 (s, 6H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 14.1 (1C), 19.6 (1C), 20.9 (1C), 21.7 (1C), 22.6 (1C), 22.7 (1C), 24.8 (1C), 27.9 (1C), 32.7 (1C), 36.8 (1C), 37.2 (1C), 37.4 (1C), 38.3 (1C), 47.9 (1C), 101.7 (1C) ppm.

MS (EI, m/z): No GC-MS was obtained due to decomposition on the column.

IR (cm⁻¹): 2951 (s), 2927 (m), 2870 (m), 2828 (m), 1723 (w), 1462 (m), 1377 (m), 1309 (w), 1256 (m), 1215 (m), 1194 (m), 1172 (m), 1111 (m), 1089 (m), 1053 (s), 972 (w), 934 (w), 920 (w), 855 (m), 815 (m), 736 (w), 618 (w).

(R)-2-(4,8-dimethylnonyl)-2,5,5-trimethyl-1,3-dioxane (R-THGA-neo)

¹H NMR (300 MHz, CDCl₃): δ 0.87 (d, J=6.6 Hz, 9H), 0.91 (s, 3H), 1.01 (s, 3H), 1.04-1.61 (m, 12H) superimposed by 1.36 (s, 3H), 1.61-1.74 (m, 2H), AB signal (δ_(A)=3.44, δ_(B)=3.54, J_(AB)=11.7 Hz, 4H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 19.7 (1C), 20.4 (1C), 21.0 (1C), 22.56 (1C), 22.61 (1C), 22.71 (1C), 22.77 (1C), 24.8 (1C), 28.0 (1C), 30.0 (1C), 32.8 (1C), 37.3 (1C), 37.4 (1C), 38.2 (1C), 39.3 (1C), 70.3 (2C), 99.1 (1C) ppm.

MS (EI, m/z): 269 [(M-CH₃)⁺, 65), 199 (8), 129 (100), 109 (8), 69 (32), 55 (10), 43 (25).

IR (cm⁻¹): 2953 (s), 2925 (s), 2868 (m), 1722 (w), 1464 (m), 1394 (m), 1371 (m), 1316 (w), 1258 (m), 1212 (m), 1161 (m), 1141 (m), 1111 (s), 1095 (s), 1043 (m), 1020 (m), 951 (m), 925 (m), 907 (m) 870 (m), 855 (m), 801 (m), 792 (m), 737 (m), 677 (w), 667 (w).

(R)-6,10-dimethyl-2,2-bis(2,2,2-trifluoroethoxy)undecane (R-THGA-tfe)

¹H NMR (300 MHz, CDCl₃): δ 0.88 (d, J=6.6 Hz, 6H), 0.87 (d, J=6.4 Hz, 3H), 1.03-1.23 (m, 5H), 1.39 (s, 3H), 1.38-1.40 (m, 6H), 1.46-1.71 (m, 3H), 3.73-3.94 (m, 4H).

¹³C NMR (75 MHz, CDCl₃): δ 19.5 (1C), 21.39 (1C), 21.47 (1C), 22.58 (1C), 22.68 (1C), 24.7 (1C), 28.0 (1C), 32.6 (1C), 37.0 (1C), 37.19 (1C), 37.23 (1C), 39.3 (1C), 59.2 (q, ²J_(C,F)=32.5 Hz, 2C), 103.6 (1C), 124.1 (q, ¹J_(C,F)=279.0 Hz, 2C).

MS (EI, m/z): 365 [(M-CH₃)⁺, 1], 281 (2), 225 [(CF₃CH₂O)₂C—CH₃)⁺, 100], 153 (8), 140 (6), 83 (CF₃CH₂ ⁺, 6), 43 (7).

IR (cm⁻¹): 2955 (w), 2929 (w), 2872 (w), 1463 (w), 1419 (w), 1385 (w), 1281 (s), 1216 (w), 1156 (s), 1122 (m), 1082 (s), 972 (m), 892 (m), 861 (w), 737 (w), 679 (w), 663 (m).

(6R,10R)-2,2-dimethoxy-6,10,14-trimethylpentadecane (RR18-DM)

¹H NMR (300 MHz, CDCl₃): δ 0.83-0.89 (m, 12H), 0.98-1.45 (m, 21H), 1.46-1.65 (m, 3H), 3.18 (s, 6H).

¹³C NMR (75 MHz, CDCl₃): δ 19.68 (1C), 19.73 (1C), 21.0 (1C), 21.7 (1C), 22.6 (1C), 22.7 (1C), 24.5 (1C), 24.8 (1C), 28.0 (1C), 32.72 (1C), 32.78 (1C), 36.8 (1C), 37.28 (1C), 37.33 (1C), 37.36 (1C), 37.41 (1C), 39.4 (1C), 48.0 (2C), 101.7 (1C) ppm.

IR (cm⁻¹): 2951 (s), 2926 (s), 2869 (s), 2828 (m), 1734 (w), 1723 (w), 1216 (w), 1463 (s), 1377 (s), 1308 (w), 1255 (m), 1215 (m), 1172 (s), 1105 (s), 1090 (s), 1054 (s), 971 (w), 933 (w), 860 (s), 815 (m), 736 (w) 618 (w).

2,5,5-trimethyl-24 (4R,8R)-4,8,12-trimethyltridecyl)-1,3-dioxane (RR18-neo)

¹H NMR (300 MHz, CDCl₃): δ 0.78-0.95 (m, 15H), 0.95-1.61 (m, 19H), superimposed by 1.01 (s, 3H), 1.36 (s, 3H), 1.63-1.74 (m, 2H), AB signal δ_(A)=3.44, δ_(B)=3.55, J_(AB)=11.7 Hz, 4H) ppm.

¹³C NMR (75 MHz, CDCl₃): δ 19.72 (1C), 19.74 (1C), 20.4 (1C), 20.9 (1C), 22.56 (1C), 22.62 (1C), 22.72 (1C), 22.77 (1C), 24.5 (1C), 24.8 (1C), 28.0 (1C), 30.0 (1C), 32.8 (1C), 32.8 (1C), 37.28 (1C), 37.35 (1C), 37.42 (2C), 38.2 (1C), 39.4 (1C), 70.3 (2C), 99.1 (1C) ppm.

MS (EI, m/z): 339 [(M-CH₃)⁺, 83], 269 (5), 129 (100), 69 (21), 43 (18).

IR (cm⁻¹): 2952 (s), 2925 (s), 2867 (m), 1463 (m), 1394 (m), 1372 (m), 1258 (m), 1211 (m), 1189 (w), 1141 (w), 1100 (s), 1043 (m), 1020 (m), 951 (w), 925 (w), 907 (m), 858 (m), 792 (w), 737 (w), 677 (w).

(6R,10R)-6,10,14-trimethyl-2,2-bis(2,2,2-trifluoroethoxy)pentadecane (RR18-tfe)

¹H NMR (600 MHz, CDCl₃): δ 0.86 (d, J=6.6 Hz, 3H), 0.879 (d, J=6.6 Hz, 3H), 0.882 (d, J=6.6 Hz, 3H), 0.884 (d, J=6.6 Hz, 3H), 1.03-1.46 (m, 18H), superimposed by 1.40 (s, 3H), 1.54 (qqt, J=6.6, 6.6, 6.6 Hz, 1H), 1.60-1.70 (m, 2H), 3.77-3.90 (m, 4H) ppm.

¹³C NMR (151 MHz, CDCl₃): δ 19.6 (1C), 19.7 (1C), 21.4 (1C), 21.5 (1C), 22.6 (1C), 22.7 (1C), 24.5 (1C), 24.8 (1C), 28.0 (1C), 32.6 (1C), 32.8 (1C), 37.0 (1C), 37.24 (1C), 37.30 (1C), 37.34 (1C), 37.43 (1C), 39.4 (1C), 59.2 (q, ²J_(C,F)=35.0 Hz, 2C), 103.6 (1C), 124.0 (q, ¹J_(C,F)=277.0 Hz, 2C) ppm.

MS (EI, m/z): 435 [(M-CH₃)⁺, 1], 351 (1), 250 (1), 225 [(CF₃CH₂O)₂C—CH₃ ⁺, 100], 153 (7), 140 (5), 83 (CF₃CH₂ ⁺, 3), 43 (6).

IR (cm⁻¹): 2954 (m), 2927 (m), 2871 (w), 1463 (w), 1419 (w), 1384 (w), 1281 (s), 1215 (w), 1157 (s), 1123 (m), 1082 (s), 972 (s), 892 (m), 861 (w), 737 (w), 679 (w), 663 (m).

Experiment E7 Combining the Hydrogenated Ketals (Step d)

The hydrogenated ketals from the corresponding unsaturated ketals having the Z- or the ZZ-configuration have been combined with the hydrogenated ketals from the corresponding unsaturated ketals having the E- or the EE-configuration obtained in the experiments of Experiment E6:

Experiment E8 Hydrolysis of Hydrogenated Ketals

After the asymmetric hydrogenation of ketals as shown in experiment E6, the hydrogenated ketals obtained were hydrolysed to (R)-6,10-dimethylundecan-2-one or (6R,10R)-6,10,14-trimethylpentadecan-2-one, respectively.

Method 1—Neopentyl Ketals, Dimethyl Ketals from Asymmetric Hydrogenation Reactions in Dichloromethane

A sample of the reaction mixture from the asymmetric hydrogenation reaction (1-2 ml) was stirred with an equal volume of 1M aqueous solution of hydrochloric acid at room temperature for 1 hour. Dichloromethane (2 ml) was added and the layers were separated. The aqueous layer was washed with dichloromethane (2 ml) twice. The combined organic layers were evaporated under reduced pressure to yield the ketone as a colourless to pale-yellow oil. The crude ketone was then analysed for purity and isomer ratio.

Method 2—Ethylene Glycol Ketals, Bis(Trifluoroethanol) Ketals and Dimethyl Ketals from Asymmetric Hydrogenation Reactions in Trifluoroethanol

A sample of the reaction mixture from the asymmetric hydrogenation reaction (1-2 ml) was stirred with 0.5 ml of a solution of 9:1:0.2 (by volume) methanol:water:trifluoroacetic acid at 40° C. for 1 hour. Dichloromethane (2 ml) and water (2 ml) were added and the layers were separated. The aqueous layer was washed with dichloromethane (2 ml) twice. The combined organic layers were evaporated under reduced pressure to yield the ketone as a colourless to pale-yellow oil. The crude ketone was then analysed for purity and isomer ratio.

Experiment E9 Preparation of Additives

The additives tetraisopropyl orthotitanate (Ti(OiPr)₄), yttrium triflate (Y(OTf)₃), sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBAr_(F)) and trimethylaluminum (TMA) are commercially available and were used as received.

-   TMA/TFE: A 2 M TMA (TMA: trimethylaluminum (Al(CH₃)₃)) solution in     heptane (1 mmol) was quenched with TFE (3.1 mmol), leading to small     excess of free TFE. This additive is used after being been freshly     prepared.

Experiment E10 Asymmetric Hydrogenations of Ketones in the Presence of Additives (Steps b/c/d)

An autoclave vessel was charged under nitrogen with chiral iridium complex of formula (III-F) of the R configuration at the chiral centre marked by *. Z-DHGA or ZZ-FA (conc.) as indicated in tables 5a or 5b, solvent as indicated in tables 5a or 5b and an additive as indicated in tables 5a or 5b. The reaction vessel was closed and pressurized with molecular hydrogen to the pressure (pH₂) of 50 bar. The reaction mixture was stirred at room temperature for 20 hours under hydrogen. Than the pressure was released and the assay yield and the stereoisomer distribution of the fully hydrogenated product was determined. The catalyst loading (S/C) is defined as mmol ketone (“substrate”)/mmol chiral iridium complex.

TABLE 5a Hydrogenation of Z-DHGA. The effect of additives. 50 51 Ketone to be hydrogenated Z-DHGA Z-DHGA conc.¹ [mol/L] 1.0 0.8 S/C 5′000 5′000 Solvent DCM DCM Additive — TMA/TFE Additive concentration [mol-%]² — 5 Assay yield [area-%] 1 40 (R)-6,10-dimethylundecan-2-one [%] n.d.³ 98.3 (S)-6,10-dimethylundecan-2-one [%] n.d.³ 1.7 ¹conc. = mol ketone/L solvent ²relative to the molar amount of Z-DHGA. ³n.d. = not determined (due to low assay yield).

TABLE 5b Hydrogenation of ZZ-FA (0.2M in 2,2,2-trifluorethanol (TFE). The effect of the additives. 52 53 54 Ketone to be hydrogenated ZZ-FA ZZ-FA ZZ-FA S/C 2000 2000 2000 Solvent TFE TFE TFE Additive — Y(OTf)₃ Ti(OiPr)₄ Additive concentration [mol-%]¹ — 0.2 14 Assay yield [area-%] 9 76 53 Isomer-Distribution² (RR) [%] 89.9 92.8 91.8 ((SS) + (RS)) [%] 5.0 3.4 3.9 (SR) [%] 5.1 3.8 4.3 ¹relative to the molar amount of ZZ-FA ²(SS) stands for the (6S,10S)-isomer, (RR) stands for the (6R,10R)-isomer, (SR) stands for the (6S,10R)-isomer, (RS) stands for the (6R,10S)-isomer of 6,10,14-trimethylpentadecan-2-one.

Accordingly E-DHGA or EE-FA, respectively, was asymmetrically hydrogenated with chiral iridium complex of formula (III-F) of the S configuration at the chiral centre marked by * under the same conditions which yielded (R)-6,10-dimethylundecan-2-one or (6R,10R)-6,10,14-trimethylpentadecan-2-one, respectively, in comparable yield and purity as shown in tables 5a and 5b, and were combined with the corresponding reaction products shown in tables 5a and 5b (step d).

Experiment E11 Asymmetric Hydrogenations of Ketals in the Presence of Additives (Steps b/c/d)

An autoclave vessel was charged under nitrogen with chiral iridium complex of formula (III-F) of the R configuration at the chiral centre marked by *, the ketal Z-DHGA-en or Z-DHGA-neo in a concentration of 0.2 mol ketal/L solvent (DCM or TFE) and an additive as indicated in table 6. The reactive vessel was closed and pressurized with molecular hydrogen to the pressure 50 bar and stirred at room temperature during 20 hours under hydrogen. Then the pressure was released and the assay yield and the stereoisomer distribution of the fully hydrogenated product were determined. In case of ketals the assay yield and the stereoisomer distribution have been determined after the hydrolysis of the ketal by acid as indicated in experiment E8. The catalyst loading (S/C) is defined as mmol ketal (“substrate”)/mmol chiral iridium complex.

TABLE 6 Hydrogenation of different ketals of Z-DHGA at pressure of molecular hydrogen (pH₂) of 50 bar and stirring at room temperature during 20 hours. The effect of the additives. 55 56 57 58 59 60 Ketal to be Z-DHGA- Z-DHGA- Z-DHGA- Z-DHGA- Z-DHGA- Z-DHGA- hydrogenated en en en en neo neo conc.¹ [mol/L] 0.2 0.2 0.2 0.2 0.2 0.2 S/C 5′000 10′000 10′000 52′000 20′000 20′000 Solvent³ DCM DCM TFE TFE TFE TFE Additive — — NaBAr_(F) TMA⁴ — TMA⁴ Additive concent- — — 0.014 100 — 10 ration [mol-%]² Assay yield [area-%] 84 39 46 93 4 63 Isomer-Distribution^(5,6) (R) [%] 98.6 98.4 97.5 98.1 85.4 98.8 (S) [%] 1.4 1.6 2.5 1.9 14.6 1.2 ¹conc. = mol ketal/L solvent ²relative to the molar amount of ketal of Z-DHGA ³TFE = 2,2,2-trifluoroethanol; DCM = dichloromethane ⁴TMA is quenched by adding into the solvent TFE ⁵(R) stands for the R-isomer, (S) stands for the S-isomer of the corresponding ketal of 6,10-dimethylundecan-2-one ⁶is determined as ketone after hydrolysis of the ketal

Accordingly E-DHGA-en or E-DHGA-neo, respectively, was asymmetrically hydrogenated with chiral iridium complex of formula 011-F) of the S configuration at the chiral centre marked by * under the same conditions which yielded the ethylene glycol ketal or the neopentyl ketal of (R)-6,10-dimethylundecan-2-one, respectively, in comparable yield and purity as shown in table 6, and were combined with the corresponding reaction products shown in table 6 (step d). The ketals have been hydrolyzed to (R)-6,10-dimethylundecan-2-one as in described in example E8. 

1. A process of manufacturing a compound of formula (I-A) or (I-B) or an acetal or a ketal thereof from a mixture of E/Z isomers of compound of formula (I) or (II) or an acetal or a ketal thereof

wherein Q stands for H or CH₃ and m and p stand independently from each other for a value of 0 to 3 with the proviso that the sum of m and p is 0 to 3, and where a wavy line represents a carbon-carbon bond which is linked to the adjacent carbon-carbon double bond so as to have said carbon-carbon double bond either in the Z or in the E-configuration and where the substructures in formula (I) and (II) represented by s1 and s2 can be in any sequence; and wherein the double bond having dotted lines (

) in formula (I) or (II) represent either a single carbon-carbon bond or a double carbon-carbon bond; comprising the steps a) separating the isomers having E-configuration from the isomers having Z-isomers in the mixture of isomers of compound of formula (I) or (II) or the acetal or ketal thereof; b) submitting the isomers having the E-configuration of compound of formula (I) or (II) or the acetal or ketal thereof to hydrogenation by molecular hydrogen in the presence of a chiral iridium complex of formula (III) having the S-configuration at the stereogenic centre indicated by *; c) submitting the isomers having the Z-configuration of compound of formula (I) or (II) or the acetal or ketal thereof to hydrogenation by molecular hydrogen in the presence of a chiral iridium complex of formula (III) having the R-configuration at the stereogenic centre indicated by *; and optionally step d) d) combining the hydrogenated products of step b) and c);

wherein n is 1 or 2 or 3, preferred 1 or 2; X¹ and X² are independently from each other hydrogen atoms, C₁₋₄-alkyl, C₅₋₇-cycloalkyl, adamantyl, phenyl (optionally substituted with one to three C₁₋₅-alkyl, C₁₋₄-alkoxy, C₁₋₄-perfluoroalkyl groups and/or one to five halogen atoms)), benzyl, 1-naphthyl, 2-naphthyl, 2-furyl or ferrocenyl; Z¹ and Z² are independently from each other hydrogen atoms, C₁₋₅-alkyl or C₁₋₅-alkoxy groups; or Z¹ and Z² stand together for a bridging group forming a 5 to 6 membered ring; Y^(⊖) is an anion, particularly selected from the group consisting of halide, PF₆ ⁻, SbF₆ ⁻, tetra(3,5-bis(trifluoromethyl)phenyl)borate(BAr_(F) ⁻), BF₄ ⁻, perfluorinated sulfonates, preferably F₃C—SO₃ ⁻ or F₉C₄—SO₃ ⁻; ClO₄ ⁻, Al(OC(CF₅)₄ ⁻, Al(OC(CF₃)₃)₄ ⁻, N(SO₂CF₃)₂ ⁻N(SO₂C₄F₉)₂ ⁻ and B(C₆F₅)₄ ⁻; R¹ represents either phenyl or o-tolyl or m-tolyl or p-tolyl or a group of formula (IVa) or (IVb) or (IVc)

wherein R² and R³ represent either both H or a C₁-C₄-alkyl group or a halogenated C₁-C₄-alkyl group or represent a divalent group forming together a 6-membered cycloaliphatic or an aromatic ring which optionally is substituted by halogen atoms or by C₁-C₄-alkyl groups or by C₁-C₄-alkoxy groups R⁴ and R⁵ represent either both H or a C₁-C₄-alkyl group or a halogenated C₁-C₄-alkyl group or a divalent group forming together a 6-membered cycloaliphatic or an aromatic ring which optionally is substituted by halogen atoms or by C₁-C₄-alkyl groups or by C₁-C₄-alkoxy groups; R⁶ and R⁷ and R⁸ represent each a C₁-C₄-alkyl group or a halogenated C₁-C₄-alkyl group; R⁹ and R¹⁰ represent either both H or a C₁-C₄-alkyl group or a halogenated C₁-C₄-alkyl group or a divalent group forming together a 6-membered cycloaliphatic or an aromatic ring which optionally is substituted by halogen atoms or by C₁-C₄-alkyl groups or by C₁-C₄-alkoxy groups; and wherein * represents a stereogenic centre of the complex of formula (III).
 2. The process according to claim 1 wherein the compound of formula (I) or (II) are selected from the group consisting of 3,7-dimethyloct-6-enal, 3,7-dimethylocta-2,6-dienal, 3,7-dimethyloct-2-enal, 6,10-dimethylundeca-3,5,9-trien-2-one, 6,10-dimethylundeca-5,9-dien-2-one, 6,10-dimethylundec-5-en-2-one, 6,10-dimethylundec-3-en-2-one, 6,10,14-trimethylpentadeca-5,9,13-trien-2-one, 6,10,14-trimethylpentadeca-5,9-dien-2-one, 6,10,14-trimethylpentadec-5-en-2-one and (R)-6,10,14-trimethylpentadec-5-en-2-one as well as all their possible E/Z-isomers.
 3. The process according to claim 1 wherein the compound of formula (I) or (II) is of formula (II) and particularly is selected from the group consisting of 6,10-dimethylundeca-3,5,9-trien-2-one, 6,10-dimethylundeca-5,9-dien-2-one, 6,10-dimethylundec-5-en-2-one, 6,10-dimethylundec-3-en-2-one, 6,10-dimethylundec-3,5-diene-2-one, 6,10,14-trimethylpentadeca-5,9,13-trien-2-one, 6,10,14-trimethylpentadeca-5,9-dien-2-one, 6,10,14-trimethylpentadec-5-en-2-one and (R)-6,10,14-trimethylpentadec-5-en-2-one as well as all their possible E/Z-isomers.
 4. The process according to claim 1 wherein the acetal or ketal of the compound of formula (I) or (II) is obtained by the reaction of the compound of formula (I) or (II) with an alcohol, particularly a monol or a diol, preferably an alcohol which is halogenated C₁-C₈-alkyl alcohol or which is selected from the group consisting of ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, butane-1,3-diol, butane-1,2-diol, butane-2,3-diol, 2-methylpropane-1,2-diol, 2-methylpropane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 1,2-dimethylpropane-1,3-diol, 3-methylpentane-2,4-diol and 2-(hydroxymethyl)cyclohexanol, benzene-1,2-diol and cyclohexane-1,2-diols.
 5. The process according to claim 1 wherein R¹ in formula (III) of the chiral iridium complex of formula is selected from the group consisting of


6. The process according to claim 1 wherein the chiral iridium complex is present during the hydrogenation in an amount in the range from 0.0001 to 5 mol-%, preferably from about 0.001 to about 2 mol-%, more preferably from about 0.001 to about 1 mol-%, most preferably from 0.001 to 0.1 mol-%, based on the amount of the compound of formula (I) or (II) or the acetal or ketal thereof.
 7. The process according to claim 1 wherein the separation of isomers in step a) is done by distillation.
 8. The process according to claim 1 wherein the hydrogenation is done in the presence of an additive which is selected from the group consisting of organic sulfonic acids, transition metal salts of organic sulfonic acids, metal alkoxides, aluminoxanes, alkyl aluminoxanes and B(R)_((3-v))(OZ)_(v); wherein v stands for 0, 1, 2 or 3 and R stands for F, a C₁₋₆-alkyl, a halogenated C₁₋₆-alkyl, an aryl or halogenated aryl group; and Z stands a C₁₋₆-alkyl, a halogenated C₁₋₆-alkyl, an aryl or halogenated aryl group.
 9. The process according to claim 8, wherein the catalyst is selected from the group consisting of triflic acid, alkyl aluminoxanes, particularly methyl aluminoxane, ethyl aluminoxane, tetra alkoxy titanates, B(R)_((3-v))(OZ)_(v); particularly tri-isopropylborate and triethylborane and BF₃, preferably in the form of a BF₃ etherate.
 10. Ketal of formula (XX-A)

wherein Q¹ and Q² stand either individually or both for a C₁-C₁₀ alkyl group or a halogenated C₁-C₁₀ alkyl group; or form together a C₂-C₆ alkylene group or a C₆-C₈ cycloalkylene group; and where a wavy line represents a carbon-carbon bond which is linked to the adjacent carbon-carbon double bond so as to have said carbon-carbon double bond either in the Z or in the E-configuration; and wherein the double bond having dotted lines (

) represent either a single carbon-carbon bond or a double carbon-carbon bond.
 11. Ketal of formula (XX-B)

wherein Q¹ and Q² stand either individually or both for a C₁-C₁₀ alkyl group or a halogenated C₁-C₁₀ alkyl group; or form together a C₂-C₆ alkylene group or a C₆-C₈ cycloalkylene group; and where a wavy line represents a carbon-carbon bond which links the adjacent carbon-carbon double bond so as to have said carbon-carbon double bond either in the Z or in the E-configuration.
 12. Acetal of formula (XX-C)

wherein Q¹ and Q² stand either individually or both for a C₁-C₁₀ alkyl group or a halogenated C₁-C₁₀ alkyl group; or form together a C₂-C₆ alkylene group or a C₆-C₈ cycloalkylene group; and wherein the double bond having dotted lines (

) represent either a single carbon-carbon bond or a double carbon-carbon bond; and wherein a wavy line represents a carbon-carbon bond which is linked to an adjacent single carbon bond (

representing —) or to an adjacent carbon-carbon double bond (

representing ═) so as to have said carbon-carbon double bond either in the Z or in the E-configuration.
 13. Acetal or ketal of formula (XXI-A) or (XXI-B) or (XXI-C) or (XXI-D)

wherein Q stands for H or CH₃ and m and p stand independently from each other for a value of 0 to 3 with the proviso that the sum of m and p is 0 to 3, wherein the double bond having dotted lines (

) in the above formulae represents either a single carbon-carbon bond or a double carbon-carbon bond; and wherein a wavy line represents a carbon-carbon bond which is linked to an adjacent single carbon bond (

representing —) or to an adjacent carbon-carbon double bond (

representing ═) so as to have said carbon-carbon double bond either in the Z or in the E-configuration.
 14. Composition comprising at least one ketal of formula (XI) or (XII) and at least one chiral iridium complex of formula (III)

wherein Q stands for H or CH₃ and m and p stand independently from each other for a value of 0 to 3 with the proviso that the sum of m and p is 0 to 3, and where a wavy line represents a carbon-carbon bond which is linked to the adjacent carbon-carbon double bond so as to have said carbon-carbon double bond either in the Z or in the E-configuration and where the substructures in formula (I) and (II) represented by s1 and s2 can be in any sequence; and wherein the double bond having dotted lines (

) in formula (XI) or (XII) represent either a single carbon-carbon bond or a double carbon-carbon bond; and wherein Q¹ and Q² stand either individually or both for a C₁-C₁₀ alkyl group or a halogenated C₁-C₁₀ alkyl group; or form together a C₂-C₆ alkylene group or a C₆-C₈ cycloalkylene group.

wherein n is 1 or 2 or 3, preferred 1 or 2; X¹ and X² are independently from each other hydrogen atoms, C₁₋₄-alkyl, C₅₋₇-cycloalkyl, adamantyl, phenyl (optionally substituted with one to three C₁₋₅-alkyl, C₁₋₄-alkoxy, C₁₋₄-perfluoroalkyl groups and/or one to five halogen atoms)), benzyl, 1-naphthyl, 2-naphthyl, 2-furyl or ferrocenyl; Z¹ and Z² are independently from each other hydrogen atoms, C₁₋₅-alkyl or C₁₋₅-alkoxy groups; or Z¹ and Z² stand together for a bridging group forming a 5 to 6 membered ring; Y^(⊖) is an anion, particularly selected from the group consisting of halide, PF₆ ⁻, SbF₆ ⁻, tetra(3,5-bis(trifluoromethyl)phenyl)borate(BAr_(F) ⁻), BF₄ ⁻, perfluorinated sulfonates, preferably F₃C—SO₃ ⁻ or F₉C₄—SO₃ ⁻; ClO₄ ⁻, Al(OC₆F₅)₄ ⁻, Al(OC(CF₃)₃)₄ ⁻, N(SO₂CF₃)₂ ⁻N(SO₂C₄F₉)₂ ⁻ and B(C₆F₅)₄ ⁻; R¹ represents either phenyl or o-tolyl or m-tolyl or p-tolyl or a group of formula (IVa) or (IVb) or (IVc)

wherein R² and R³ represent either both H or a C₁-C₄-alkyl group or a halogenated C₁-C₄-alkyl group or represent a divalent group forming together a 6-membered cycloaliphatic or an aromatic ring which optionally is substituted by halogen atoms or by C₁-C₄-alkyl groups or by C₁-C₄-alkoxy groups R⁴ and R⁵ represent either both H or a C₁-C₄-alkyl group or a halogenated C₁-C₄-alkyl group or a divalent group forming together a 6-membered cycloaliphatic or an aromatic ring which optionally is substituted by halogen atoms or by C₁-C₄-alkyl groups or by C₁-C₄-alkoxy groups; R⁶ and R⁷ and R⁸ represent each a C₁-C₄-alkyl group or a halogenated C₁-C₄-alkyl group; R⁹ and R¹⁰ represent either both H or a C₁-C₄-alkyl group or a halogenated C₁-C₄-alkyl group or a divalent group forming together a 6-membered cycloaliphatic or an aromatic ring which optionally is substituted by halogen atoms or by C₁-C₄-alkyl groups or by C₁-C₄-alkoxy groups; and wherein * represents a stereogenic centre of the complex of formula (III).
 15. Use of ketal according to claim 10, as intermediate for the synthesis of tocopherols, vitamin K1, as well as for the synthesis of compositions in the field of flavours and fragrances or pharmaceutical products. 